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Olinda

Olinda is a historic city in Pernambuco, Brazil, in the Northeast Region. It is located on the country's northeastern Atlantic Ocean coast, in the Metropolitan Region of Recife, the state capital. It has a population of 393,115 people, covers 41.681 km2, and has a population density of 9437 PD/km2. It is noted as one of the best-preserved colonial cities in Brazil and has been inhabited since 1535.

As the former capital of the Captaincy of Pernambuco during the colonial era, Olinda has many historical buildings—the center was declared a UNESCO World Heritage Site in 1982—and a rich culture. The Carnaval of Olinda, a popular street party, is very similar to traditional Portuguese carnivals, with the addition of African influenced dances, reflecting the history of the Northeast. All the festivities are celebrated on the streets with no bleachers or roping, and, unlike in other cities, admission is free. There are hundreds of small musical groups (sometimes featuring a single performer) in many genres.

History

Several indigenous tribes occupied the coast of Northeastern Brazil for several thousand years, and the hills of the present day municipality of Olinda had settlements of Caetés and Tupinambá tribes, which were frequently at war. French mercenaries are thought to be the first Europeans to reach the region, but the Portuguese exploited intertribal rivalries and managed to build a stronghold on the former Caeté village on a high hill. Recent studies by the Federal University of Pernambuco have uncovered new evidence of the pre-colonial population of the area.

The settlement of Olinda was founded in 1535 by Duarte Coelho Pereira, from Portugal; it was elevated to a town on March 12, 1537. It was made the seat of the Roman Catholic Territorial Prelature of Pernambuco in 1614, becoming the Diocese of Olinda in 1676. The economy of the region was dominated by the production of sugarcane. This, combined with the importing of slaves from Africa to support cultivation made Olinda a colonial stronghold.

Olinda was the capital of the Portuguese hereditary captaincy of Pernambuco, but was burned by Dutch invaders. The Portuguese built their town on the hill, for practical purposes (eg, sewers) and to make it easier to defend. In the 17th century the Kingdom of Portugal was united with Spain (the 1580-1640 Iberian Union). Taking advantage of this period of Portuguese weakness, the area around Olinda and Recife was occupied by the Dutch who gained access to the Portuguese sugarcane plantations. John Maurice, Prince of Nassau-Siegen was appointed as the governor of the Dutch possessions in Brazil in 1637 by the Dutch West India Company on recommendation of Frederick Henry. He landed at Recife, the port of Pernambuco and the chief stronghold of the Dutch, in January 1637. By a series of successful expeditions, he gradually extended the Dutch possessions from Sergipe on the south to São Luís de Maranhão in the north. He likewise conquered the Portuguese possessions of Saint George del Mina, Saint Thomas, and Luanda, Angola, on the west coast of Africa. After the dissolution of the Iberian Union in 1640, Portugal would reestablish its authority over the lost territories of the Portuguese Empire, including the former Dutch Brazil. Sugarcane plantation slavery would continue to be a source of wealth in Olinda until the Lei Áurea ("Golden Law") abolished slavery in an independent Brazil in 1888.

Olinda declined in importance after the Dutch invasion. Recife became the capital of Pernambuco in 1827, and Olinda is part of the greater Recife metropolitan area. Due to the historic position of the city, its cathedral, a World Heritage Site, called São Salvador do Mundo, remains the primary seat of the Roman Catholic Archdiocese of Olinda and Recife, with a co-cathedral in Recife. Olinda also has a Minor Basilica, again a World Heritage Site (Minor): Basílica Abacial do Mosteiro de São Bento de Olinda.

Besides its natural beauty, Olinda is also one of Brazil's main cultural centers: in 1982 it was declared a World Heritage Site by UNESCO. The city relives the magnificence of the past every year during the large Carnival, to the rhythms of frevo, maracatu and other northeast music and dances.

Geography
Olinda is located on the coast of the state of Pernambuco, six kilometers north of the center of Recife. It is bordered by the Atlantic Ocean to the east, the municipality of Paulista to the north, and Recife to the south and west. It is part of the Metropolitan Region of Recife (RMR).

The average elevation is 16 m above sea level. The landscapes is made of plains and hills, some of them steep. Olinda is mostly drained by the Paratibe River (55.13% of the territory), with the remainder drained by the Capibaribe River. The municipality is in the Atlantic Forest ecoregion.

Olinda has a tropical monsoon type climate (Köppen-Geiger: Am), typical of the eastern section of the northeastern Brazilian coast, with average monthly temperatures consistently above 18 °C, little diurnal variation in temperature, abundant rainfall most of the year, and high relative humidity.

Economy

The main economic activities in Olinda are based in tourism, commerce, transportation industry and artcraft. The tourist sector has a boom every Carnival when thousands of people are in the old historic town center.

Economic indicators
Economy by Sector

title: Olinda


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Paulista

Paulista is a municipality in Pernambuco, Brazil, with a population of 334,376 as of 2020. It has the highest Human Development Index (HDI) of the Recife metropolitan area. It is the birthplace of footballer Rivaldo and is also famous for its beaches, including Maria Farinha with the giant Veneza water park. It was incorporated as a city in 1935.

History
In 1535 Paulista was a village, with two parishes, Paratibe and Maranguape, and formed part of the then village of Olinda. In the mid-16th century, the lands of Paratibe were donated by Coelho to Jerônimo de Albuquerque, services rendered to the Dubuquerque colony. Jerônimo de Albuquerque, after a while, ceded the lands of Paratibe to Gonçalo Mendes Leitão, at the time of marrying his daughter. Later, with the death of Mendes Leitão, his heirs sold them as properties, dividing from then on into Paratibe de Cima and Paratibe de Baixo (Upper Paratibe and Lower Paratibe). In 1856, the parish of Maranguape was acquired by João Fernandes Vieira and at the end of this century, in the year 1689, the two parishes, Paratibe and Maranguape, were sold to the pioneer of São Paulo, Manoel Álvares de Morais Navarro, known as "Paulista", giving rise to the current name of the city.

The later centuries were characterized by both political and economic growth for the city. Paulista was the second district of Olinda until 1935, which became an independent municipality and is currently formed by the districts of Paratibe, Arthur Lundgren I, Arthur Lundgren II, Jardim Paulista Baixo, Jardim Paulista Alto, Conceição, Janga, Pau Amarelo, Nobre, Maranguape I, Maranguape II, Jardim Maranguape, Alameda Paulista, Maria Farinha, Engenho Maranguape and Mirueira.

Anthem
It was made by Joel Andrade.

Portuguese Lyrics
O antigo Engenho de Manuel Navarro

Cresceu e para o mundo despontou

É hoje palco de um progresso imensurável

Paulista, símbolo da graça e do labor!

Em teu rico solo, o choro é riso

Doce paraíso encantador

Onde os dias têm mais luz

Onde as estrelas têm mais fulgor

Em cima, o céu é mais azul, é mais bonito

Em baixo, a brisa tem aroma de eucalipto

Teu povo é mais ordeiro e mais gentil

Paulista, fração linda do Brasil (BIS)

Qual grande lençol verde se agitando

Teu mar faz do teu leste atração

Enquanto o Sol que é bem mais Sol sobre teu solo

Esquenta o ar, esquenta a vida esquenta o chão

És o apogeu de um sonho lindo

Esplendor de um dia de verão

Onde a paz reside em paz

Onde as roseiras bem mais rosas dão

Em cima, o céu é mais azul e mais bonito

Embaixo, a brisa tem aroma de eucalipto

Teu povo é mais ordeiro e mais gentil

Paulista, fração linda do Brasil!

English Lyrics
The old Mill of Manuel Navaro

Grew and for the world it emerged

Is today an immeasurable progress stage

Paulista, symbol of grace and labor!

In your rich soil, the cry is laughter

Sweet charming paradise

Where the days have more light

Where the stars have more shine

Above, the sky is bluer, is more beautiful

Below, the wind has a eucalyptus scent

Your people are more orderly and kinder

Paulista, beautiful fraction of Brazil (BIS)

Which big green sheet shaking

Your east makes your sea attractive

While the sun is way more sun in your soil

Heat the air, heat the life heat the ground

Are the height of a beautiful dream

The splendor of a summer day

Where peace resides in peace

Where the rose bushes way more roses give

Above, the sky is bluer, is more beautiful

Below, the wind has a eucalyptus scent

Your people are more orderly and kinder

Paulista, beautiful fraction of Brazil

Beaches

 * Conceição Beach - At 2 km long with many coconut trees, this beach has calm and very deep water. Also has many bars and tents.
 * Janga Beach - an urban beach with artificial reefs
 * Maria Farinha Beach - features quiet and shallow waters. At low tide, it is possible to see the reefs, and at this time, the beach has almost no waves.
 * Pau Amarelo Beach - features quiet water and a formation of sand banks, which give rise to small sandbar islets and natural pools.

The beaches of Paulista are a nesting ground for endangered hawksbill sea turtles.

Economy
In the municipality of Paulista, activities related to services, commerce and industry predominate. Tourism is also responsible for attracting enterprises to the municipality with the implementation of hotels, restaurants, commercial points, and marinas. In Paulista, the industrial park of Paratibe is also located, which houses companies from different sectors, stimulating the region's economy and generating employment for the population.

The municipality is part of the Metropolitan Region of Recife, which polarizes economic flows, with a predominance of the service sector and functions as a distribution center for goods. In addition to concentrating a greater number of processing industries in the State, another pillar of the metropolitan economy is the agro-industry, focused on the alcohol and sugar sectors. Also noteworthy is the cultivation of fruits and vegetables, such as bananas, coconuts, yams, manioc, among others.

Economic Indicators
Economy by Sector

Notable people

 * Heider Dias Sotero, footballer

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Paulista


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Rivaldo

Rivaldo Vítor Borba Ferreira (born 19 April 1972), known simply as Rivaldo, is a Brazilian former footballer who played mainly as an attacking midfielder but also as a second striker, and on occasion deployed as a wide midfielder or as a winger. Rivaldo is regarded as one of the greatest, most skillful, and most creative players of all time. He was renowned for his bending free kicks, bicycle kicks, feints, powerful ball striking from distance, and ability to both score and create goals. In 1999, he won the Ballon d'Or and was named FIFA World Player of the Year. In 2004, he was named by Pelé in the FIFA 100 list of the world's greatest living players. With success at club and international level, he is one of nine players to have won the FIFA World Cup, the UEFA Champions League and the Ballon d'Or.

Rivaldo started his career in 1991 with Brazilian club Santa Cruz, going on to have spells at Mogi Mirim, a loan spell at Corinthians, and Palmeiras. In 1996, he moved to Europe with Spanish side Deportivo de La Coruña, where his performances in his only season there led him to sign for Barcelona in 1997. At Barcelona, he formed a successful partnership with Dutch international Patrick Kluivert, and won consecutive La Liga titles in 1998 and 1999, as well as the 1998 Copa del Rey. Rivaldo notably scored a hattrick against Valencia in June 2001 which qualified Barcelona for the 2001-02 UEFA Champions League; the last goal was a last minute 20-yard bicycle kick winner and the hattrick itself is often ranked as the greatest ever. During his five-year tenure there, he scored 130 goals, ranking him among Barcelona's highest goalscorers of all time.

In 2002, Rivaldo signed for Italian club A.C. Milan, winning the Coppa Italia and the UEFA Champions League in his only season there, however, his performances were underwhelming and he cancelled his contract with Milan in late 2004. He went on to play for Cruzeiro, Olympiacos, AEK Athens, Bunyodkor, a loan spell at São Paulo, Kabuscorp and São Caetano. In March 2014, Rivaldo announced his retirement from professional football, however since June 2015 he made appearances for Mogi Mirim, before retiring again in August 2015.

From 1993 to 2003, Rivaldo played 74 matches and scored 35 goals for Brazil and is the seventh highest goalscorer for the country. He helped Brazil reach the final of the 1998 FIFA World Cup and won the 1999 Copa América where he was named player of the tournament. Rivaldo starred in an attacking trio with Ronaldo and Ronaldinho in the 2002 FIFA World Cup winning team. Scoring in five of Brazil's seven games at the tournament, Rivaldo was named in the FIFA World Cup All-Star Team in 2002 having also previously been selected in 1998. He is an inductee to the Brazilian Football Museum Hall of Fame.

Early life
Born in Recife, Brazil, Rivaldo had a poor upbringing in the favelas of the city. His physical appearance still marks the poverty he experienced in his childhood: malnourishment-caused bowleggedness and the loss of several teeth. Predominantly left footed, Rivaldo began his professional career at the age of 16, when he signed with Paulistano Futebol Clube in 1989, despite the Paulistano coaches believing him too physically weak to succeed. Rivaldo's father Romildo was killed in a road accident in 1989, but Rivaldo signed his first professional contract later that year.

Santa Cruz, Mogi Mirim and Corinthians
He went on to play for Santa Cruz in 1991. In 1992, he moved south to the state of São Paulo where he played for Mogi Mirim in the second tier of Brazilian football. In 1993, he moved to the state capital paulista to play for Corinthians in the first division, on loan.

Palmeiras
In the next year, he switched local allegiances and moved to Palmeiras, helping the club successfully defend its league championship in 1994 and winning Campeonato Paulista in 1996. In both 1993 and 1994, he was honoured by the authoritative publication Placar Magazine with the Bola de Ouro for the best player in his position.

Deportivo
Before the 1996 Olympics, Parma announced that they had signed Rivaldo and his teammate Amaral from Palmeiras. After the Olympics, there was a dispute, and rather than Italy, Rivaldo moved to Spain as he joined Deportivo La Coruña in La Liga. He only stayed for one season, but nonetheless it proved to be a successful one for both him and the club. Rivaldo was the joint-fourth top goalscorer of the season, with 21 goals from 41 matches, as Deportivo finished third in the league.

Barcelona
Rivaldo switched to FC Barcelona in 1997 in a transfer deal securing Deportivo a 4 billion pesetas (around $26 million) transfer fee, with Sir Bobby Robson convincing Barcelona to sign Rivaldo ahead of Steve McManaman by saying that Rivaldo would guarantee the team many goals.

In his first season at Barcelona, Rivaldo was the second top goalscorer with 19 goals in 34 matches, as Barcelona won The Double of La Liga and Copa del Rey. In 1999, he won another La Liga title with Barcelona, and once again was the league's second highest scorer with 24 goals. In 1999, Rivaldo was named FIFA World Player of the Year and he also received the Ballon d'Or. After Barcelona's unsuccessful Champions League campaign, Rivaldo was linked with a move away from Camp Nou. Then Manchester United captain Roy Keane was reported stating Rivaldo was the player he most wanted United to sign.

In his third season at Barcelona, Rivaldo fell out with manager Louis van Gaal, when he insisted playing as a playmaker rather than on the left wing. Even though he had a strained relationship with Van Gaal, Rivaldo went on to score 10 goals in the season's Champions League as the club reached the semi-finals. Van Gaal was fired in June 2000.

In the following 2000–01 season, Rivaldo was once again the second highest goalscorer of the league, with 23 goals. In the decisive last game of the season, against Champions League finalist Valencia CF, Rivaldo scored a hat-trick to win the game 3–2, pushing Barcelona ahead of Valencia to secure a place in the 2001–02 Champions League. Frequently ranked the greatest hat-trick ever, his first goal was a trademark bending free kick that curled into the bottom right corner, the second saw him send the Valencia player the wrong way with a feint before a strike with little back-lift from 25 yards swerved into the bottom left corner of the net, and his match-winning third occurred after Rivaldo controlled the ball with the chest from the edge of the 18-yard box and executed an overhead bicycle kick in the 89th minute, which he regards as the best goal of his career. An ecstatic Rivaldo ripped off his jersey and started swinging it over his head during his goal celebrations, while Barcelona club president Joan Gaspart broke with convention in the stadium's VIP box by punching the air with both fists and yelling his delight next to the opposition delegation. After the game Rivaldo stated; "What happened tonight has been incredible. I dedicate the winning goal to all the players who have fought so hard all season and all the supporters who have suffered so much. I'm delighted to have made them happy with my goals." He scored a total of 36 goals that season. During his five-year tenure at Barcelona, Rivaldo scored 130 goals, ranking him among the club's highest goalscorers of all time.

Milan
Rivaldo signed a three-year deal with the Italian Serie A club Milan in 2002. With Milan, he won the Coppa Italia and the Champions League in the 2002–03 season. In August 2003, he also won the UEFA Super Cup before cancelling his contract with Milan in November that year. After leaving Milan, he briefly returned to Brazil, playing for Cruzeiro in Belo Horizonte. He came close to signing for Bolton Wanderers in 2004, though Bolton eventually pulled out of the deal. Due to his poor performances throughout the season, he won the Bidone d'Oro Award in 2003, which is given to the worst Serie A player during a particular season.

Cruzeiro
Rivaldo decided to return to Brazil in early 2004, by appointment of coach Vanderlei Luxemburgo who convinced him to play for the club, becoming Cruzeiro's major signing for the Copa Libertadores. However, his time with the team was very short, only eleven games and two goals. As reported by CNN, Rivaldo left the club after just two months due to the firing of Luxemburgo, Rivaldo's mentor earlier in his career. Rivaldo stated, "When he left, I preferred to leave as well. It was my decision because I consider Luxemburgo to be a special person."

Olympiacos
On 22 July 2004, Rivaldo joined Olympiacos of Superleague Greece. During the 2004–05 season he scored some stand out goals, one of them coming in his first derby against Panathinaikos that arguably turned out to be his most famous in an Olympiacos shirt: a bending free kick to send Olympiacos to victory over their eternal rivals. Another notable goal by Rivaldo came the following week in Olympiacos's matchday 6 UEFA Champions League group game in England against eventual champions Liverpool F.C. where he scored a deft free-kick in front of the Kop and put the Greek giants ahead. However Olympiacos were eliminated after Liverpool talisman Steven Gerrard scored with a 25-yard half volley 3 minutes from full-time. In the last game of Rivaldo's first season at Olympiacos, the club needed a victory in order to win the Alpha Ethniki championship, with Panathinaikos just one point behind. Olympiacos went on to beat Iraklis 0–1 in an away match in Thessaloniki, thanks to Rivaldo's goal, and secured the championship.

Rivaldo renewed his contract with Olympiacos for a third year, despite now being 34 years old. In July 2006, Rivaldo announced that the 2006–07 season with Olympiacos would be his last in Europe, before returning to Brazil. However, he quickly changed his decision and decided to stay for another year. The 2006–2007 season saw him score 17 goals in 27 Superleague matches. Rivaldo scored 43 goals in 81 games for Olympiacos.

AEK Athens
Rivaldo was released by Olympiacos after a dispute with the chairman of the club, Sokratis Kokkalis, who decided that he was too old to continue with the club. Later that summer, he signed for Super League club AEK Athens on 29 May 2007. His first Super League goal with the Athens' club came through a penalty in their 3–0 win against Panionios. Rivaldo had another great season and the team. After the winning match against Olympiacos with 4–0, Rivaldo showed his four fingers to the camera.

Rivaldo had stated his intention to leave Greece if the ruling went in favour of Olympiakos and AEK Athens were not declared champions. He stated: "A team that was not good enough to win the title on the pitch does not deserve the trophy."

Bunyodkor
Rivaldo announced on 25 August 2008 to a Greek Sport Radio Station that he agreed to continue his career at Bunyodkor in Uzbekistan, effective immediately, after what he described as an "extremely tempting contract offer".

Rivaldo signed a two-year contract worth €10.2 million and later signed an extension to extend the contract to 2011. On his debut for Bunyodkor, Rivaldo scored both goals in a 2–0 win. In 2009, Rivaldo became the first player in the world to score one, then two, then three, then four goals in four consecutive matches. He scored one goal in the first match and two goals in the second match against Navbahor. In the third match on 25 June 2009, Rivaldo scored a hat trick in a 4–0 win against Metallurg. In the fourth match Bunyodkor beat Sogdiana Jizzakh 5–0 and Rivaldo scored four in 17 minutes. After the end of the 2009 season, Rivaldo won UFF Topscorer award, having scored 20 league goals, and was runner up for UFF Player of the Year award. He scored 33 goals for the club in total. Rivaldo announced on 11 August 2010 on Twitter that he had cancelled his contract with Bunyodkor.

Return to Mogi Mirim
On 18 November 2010, he announced he would be returning to Mogi Mirim, the club that he had started his career in the early 1990s, through his Social Networking site, saying: "After sorting out a lot of things outside of the country, I have decided to play the Paulista 2011 for Mogi Mirim, of whom I am President." However, he joined São Paulo in January 2011.

São Paulo
On 23 January 2011, Rivaldo joined São Paulo. He scored on his debut for them in the First Division against Linense with a wonderful goal. The ball was sent over from the left hand side of the pitch, before Rivaldo controlled the ball and took it over a defender using his left knee, and finished at the near post. He spent most part of March 2011 tending injury, but came back for following fixtures such as a 1–1 draw with Palmeiras and a 2–1 win over Corinthians.

Rivaldo stated on his Twitter account that he would leave São Paulo by the end of the season: "I just want to inform everybody that on Saturday, it's going to be my last training session at São Paulo. I've been told by the club's official that this is going to be my last season here." He added: "I'm not saying goodbye to football yet. I still have a lot to accomplish. I just wish I could hang up my boots at the end of 2012."

Kabuscorp
Rivaldo joined Angolan club Kabuscorp in January 2012. On 18 March, Rivaldo scored a hat-trick against Recreativo Caala. Rivaldo left Kabuscorp in November 2012 after the expiration of his contract.

São Caetano
In January 2013, Rivaldo joined São Caetano, signing a deal that ran to December. He scored his first goal for his new club in his debut against Sport Club Corinthians Paulista, 9 February. During the following match against Clube Atlético Bragantino Rivaldo once again scored, although his team lost with 2–1. In November 2013, he left the club due to knee problems.

Second return to Mogi Mirim
In December 2013, Rivaldo joined Mogi Mirim, signing a deal that ran until 2015. His son Rivaldinho played for the club. Rivaldo had only made one league appearance for the club when he retired in July 2015.

Retirement
In March 2014, the Brazilian icon officially retired from football after a career which spanned more than 20 years, and he decided to remain as the president of Mogi Mirim to help run the club and to look after his son, Rivaldinho. In a released statement, Rivaldo commented: "My history as a player has come to the end. With tears in my eyes today I would like to thank God, my family and all the support, the affection that I received during those 24 years as a player." However, he returned to the team in June 2015. On 14 July 2015, Rivaldo and Rivaldinho scored goals in the same match for the first time as Mogi Mirim beat Macaé 3–1.

On 18 January 2019, SCC Mohammédia announced Rivaldo as their new technical director and coach for the following season. The player denied that a deal was made, as he signed a pre-contract in which the club must achieve promotion from National (third tier in the Moroccan league).

International career
In 1993, he debuted for the Brazil national football team, scoring the only goal in a friendly match against Mexico. He was selected to represent Brazil at the 1996 Summer Olympics. The Brazilian team won the bronze medal, but Rivaldo was not selected for the third place playoff.

Rivaldo returned to the Brazil national team for the 1998 FIFA World Cup, where he scored three goals en route to the final, including two in the 3–2 quarter-final win against Denmark. Brazil were defeated 3–0 by hosts France in final, failing to defend their 1994 title. Rivaldo had not been a part of the victorious Brazilian team at the 1997 Copa América tournament, but was part of the successful defence of that title at the 1999 Copa América. Rivaldo finished the tournament as the top scorer, with five goals; one being an equaliser from a free-kick in a 2–1 win over Argentina in the quarter-finals, and two in the 3–0 victory over Uruguay in the final. He was named the Most Valuable Player of the tournament.

Rivaldo had been the centre of criticism when Brazil did not win tournaments, ever since the 1996 Olympics. In the 1–0 win against Colombia in November 2000, Rivaldo was booed so heavily that he threatened to retire from playing for his country.

The zenith and nadir of Rivaldo's national team career came at the 2002 FIFA World Cup, hosted in South Korea and Japan, where he was able to erase the disappointment of the previous World Cup Final defeat, helping Brazil win their fifth World Cup. Featuring in an attacking trio with Ronaldo and Ronaldinho, dubbed "the three R's", Rivaldo scored in the first five games while Ronaldo scored in four matches. Despite a successful tournament, Rivaldo was involved in a controversial incident against Turkey. Near the end of the match, with the ball out of play, Turkish defender Hakan Ünsal kicked a ball towards Rivaldo, who was waiting at the corner flag. The ball struck his thigh, but Rivaldo fell to the ground clutching his face. The referee sent the Turkish player off with a second yellow card. After a video review, Rivaldo was fined 11,670 Swiss francs by FIFA.

Rivaldo's goal against Belgium in the second round prompted Belgian coach Robert Waseige to name him as the deciding factor. Ronaldinho assisted Rivaldo to score the equaliser against England in the quarter-finals before Ronaldinho scored the winning goal in a 2–1 victory. Brazil met Germany in the final, and went on to win the tournament with a 2–0 victory, courtesy of two goals by Ronaldo with Rivaldo involved in both goals. The first came after Rivaldo's shot was saved by German goalkeeper Oliver Kahn with Ronaldo scoring the rebound, and the second saw Rivaldo fool the German defence with a dummy as the ball ran on to Ronaldo who finished. Rivaldo was named by Brazil coach Luiz Felipe Scolari as the best player of the tournament. Rivaldo along with Ronaldo and Ronaldinho were named in the FIFA World Cup All-Star Team.

Rivaldo's last cap was on 19 November 2003 in Curitiba in a 3–3 draw with Uruguay. He played 79 minutes before being substituted for Luís Fabiano. He had scored his last goal just three days earlier from the penalty spot in a 1–1 draw with Peru. In his time with the national side, Rivaldo won 74 caps, and scored 35 goals.

Style of play
Regarded as one of the best players of his generation and also one of the greatest players of all time, Rivaldo was a skillful and creative player known for his dribbling ability, use of feints, balance, and close ball control. Despite his height, he was also extremely agile. A dead-ball specialist, Rivaldo was renowned for his bending free kicks and penalty taking, as well as his ability to score from distance with powerful strikes. Left footed and possessing excellent technique, he was also known for his ball striking from volleys, and for having a penchant for scoring from bicycle kicks.

"Apart from a right foot, Rivaldo had everything. His wiry strength allowed him to bounce off defenders, he was an outstanding dribbler, and he had a left foot that was both educated and thuggish, subtle and a sledgehammer. Brazil's bandy-legged genius was the most unstoppable footballer since Maradona."

- Rob Smyth writing for The Guardian on Rivaldo's style of play in 2008.

Although he was not a true striker, Rivaldo was a prolific goalscorer, capable of playing in several creative and offensive positions: during the prime of his career, a period where he won the Ballon d'Or and was named FIFA World Player of the Year, he was often deployed in a playmaking attacking midfield role as a classic number 10, due to his vision and passing ability, which made him an excellent assist provider. He could also function as a second striker, or as a left winger, a position which he often occupied earlier in his career, due to his acceleration and crossing ability. Although predominantly left footed, he was capable of playing on either wing.

In 2002, John Carlin of The Guardian noted that Rivaldo "combines to dazzling effect the two essential qualities of the ideal footballer: artistry and efficiency." His colleague, Rob Smyth, echoed his views in 2008, commenting: "if you could marry British will with continental skill, you would have the perfect footballer. Such a mixed recipe was thrillingly in evidence in Diego Maradona. Since then, however, perhaps only Rivaldo has fused the two qualities," noting that like the Argentinian, the Brazilian had "bronca" (the word used repeatedly in Maradona's autobiography to refer to "anger, fury, hatred, resentment, bitter discontent). Former Dutch international Ruud Gullit believed that Rivaldo's ability and qualities were often overlooked, as "he played in the same era as Brazilian counterparts Ronaldo and Ronaldinho."

International

 * Scores and results list Brazil's goal tally first, score column indicates score after each Rivaldo goal.

Honours
Palmeiras
 * Brazilian Série A: 1994
 * Campeonato Paulista: 1996
 * Copa do Brasil runner-up: 1996

Barcelona
 * La Liga: 1997–98, 1998–99
 * Copa del Rey: 1997–98
 * UEFA Super Cup: 1997

Milan
 * Coppa Italia: 2002–03
 * UEFA Champions League: 2002–03
 * UEFA Super Cup: 2003

Cruzeiro
 * Campeonato Mineiro: 2004

Olympiacos
 * Alpha Ethniki/Super League Greece: 2004–05, 2005–06, 2006–07
 * Greek Cup: 2004–05, 2005–06

Bunyodkor
 * Uzbek League: 2008, 2009, 2010
 * Uzbekistan Cup: 2008, 2010

Brazil U23
 * Summer Olympics Bronze Medalist: 1996

Brazil
 * FIFA World Cup: 2002; runner-up: 1998
 * Copa América: 1999
 * Confederations Cup: 1997
 * Umbro Cup: 1995

Individual
 * Brazilian Football Museum Hall of Fame
 * Brazilian Bola de Prata (2): 1993, 1994
 * La Liga Best Foreign Player: 1997–98
 * La Liga top assist provider: 2000–01
 * Copa del Rey Top scorer: 1997–98
 * FIFA World Cup All-Star Team (2): 1998, 2002
 * ESM Team of the Year (2): 1998–99, 1999–2000
 * World Soccer Player of the Year: 1999
 * Onze d'Or: 1999
 * Ballon d'Or: 1999
 * FIFA World Player of the Year: 1999
 * Copa América Golden Boot: 1999
 * Copa América Golden Ball: 1999
 * Trofeo EFE: 1999
 * UEFA Champions League Top scorer: 1999–2000
 * IFFHS World's Top Goal Scorer: 2000
 * FIFA World Player of the Year: Bronze award 2000
 * FIFA World Cup Silver Shoe: 2002
 * FIFA XI: 2002
 * FIFA 100
 * Alpha Ethniki Best Foreign Player (2): 2006, 2007
 * Alpha Ethniki top assist provider: 2008
 * Uzbek League Top scorer: 2009
 * Uzbek League top assist provider: 2009

title: Rivaldo


text:
Legal fiction

A legal fiction is a construct used in the law where a thing is taken to be true, which is not in fact true, in order to achieve an outcome. Legal fictions can by employed by the courts or found in legislation.

Legal fictions are different from legal presumptions which assume a certain state of facts until the opposite is proved, such as the presumption of legitimacy.

The term legal fiction is sometimes used in a pejorative way. Jeremy Bentham was a famous historical critic of legal fictions. Proponents of legal fictions, particularly of their use historically, identify legal fictions as "scaffolding around a building under construction".

Adoption
Child adoption is a legal fiction in that the adoptive parents become the legal parents, notwithstanding the lack of a biological relationship. Once an order or judgment of adoption is entered, the biological parents become legal strangers to the child, legally no longer related nor with any rights related to the child. Conversely, the adoptive parents are legally considered to be parents of the adopted child. A new birth certificate reflecting this is issued, which is a legal fiction.

Doctrine of survival
If two or more people die within a period of time or in a manner that renders it impossible to tell the order in which they died, the older of the two is considered to have died first.

The doctrine of survival, although still existing in England, has been abolished in many U.S. states by the Uniform Simultaneous Death Act.

Doe and Roe
The use of John Doe or Jane Roe to identify an undisclosed party in a lawsuit is a type of legal fiction.

The fiction of Doe and Roe being the guardians of undisclosed parties who wish to bring suit, or the names of parties unknown, remains in some jurisdictions although not in England.

The fiction about Doe being left homeless by Roe, used often in property law, however, has been abolished in every common law jurisdiction.

Ejectment
The common law had a procedure whereby title to land could be put in direct issue, called the "writ of right". The defendant could insist on trial by "wager of battle", that is trial by combat, a judicially sanctioned duel. To avoid the plaintiff staking life and limb, a tale was told in the pleadings about how one John Doe leased land from the plaintiff but was ousted by Richard Roe, who claimed a contrary lease from the defendant. Such events would lead to the "mixed action in ejectment", a procedure to determine title via trial by jury. This is the origin of the names John Doe and Richard Roe for anonymous parties. The fiction of Doe, Roe, and the leases was not challenged by the parties unless they wished to stake their life on a trial by combat. Wager of battle fell into disuse by the end of the thirteenth century though it was not abolished in England until 1819.

Reasonable man
In cases where the court must determine whether a standard has been reached, such as whether a defendant has been negligent, the court frequently uses the legal fiction of the "reasonable man". This is known as the "objective test", and is far more common than the "subjective test" where the court seeks the viewpoint of the parties (or "subjects"). Sometimes, the court may apply a "mixed test", as in the House of Lords' decision in DPP v Camplin 1978.

Jurisdiction of the Exchequer
In England, a legal fiction extended the jurisdiction of the Court of the Exchequer to all types of cases involving debt. The Exchequer had a much lighter caseload than the King's Bench and other courts in England. Litigants would commence an action in the Exchequer Court by pleading that they owed money to the King, which they could not pay because their debtor had in turn wrongfully withheld payment to them. The debt owed to the King became a legal fiction in that the original debtor was not entitled to controvert this allegation in order to oust the Exchequer from jurisdiction.

Jurisdiction of the Court of King's Bench
The Bill of Middlesex was a legal fiction used by the Court of King's Bench to gain jurisdiction over cases traditionally in the remit of the Court of Common Pleas. Hinging on the King's Bench's retaining criminal jurisdiction over the county of Middlesex, the Bill allowed it to take cases traditionally in the remit of other common law courts by claiming that the defendant had committed trespass in Middlesex. Once the defendant was in custody, the trespass complaint would be quietly dropped and other complaints (such as debt or detinue) would be substituted.

Resignation from Parliament
In 1623, a rule was declared that Members of Parliament were given a trust to represent their constituencies and, therefore, were not at liberty to resign. However, an MP who accepted an "office of profit" from the Crown (including appointment as a minister) was obliged to leave the House and seek re-election, because it was thought their independence might be compromised if they were in the monarch's pay.

The device was invented that the MP who wished to quit applied to the Crown for the post of "Steward of the Chiltern Hundreds" or "Steward of the Manor of Northstead" with no duties or income, but legally an office of profit in the monarch's gift. The first MP to avail themself of the Chiltern Hundreds to leave Parliament was John Pitt in 1751. The requirement for ministerial re-election has been abolished, but the "Chiltern Hundreds" mechanism remains to enable MPs to resign.

2019 prorogation controversy
The 2019 UK prorogation controversy was resolved through the use of legal fiction. Although the United Kingdom Supreme Court found that Prime Minister Boris Johnson's prorogation of parliament had been unlawful, it lacked the authority to order the recall of Parliament. Instead, the legal fiction was maintained that Parliament had never been prorogued; any references to prorogation were expunged from the record, and Parliament was instead recorded as being adjourned, enabling it to reassemble the next day.

Mabo v Queensland
Some legal fictions have been invalidated due to increased historical knowledge and changes in social norms, as in the Mabo case, where the High Court of Australia rejected previous authorities that held that Indigenous Australians were too "low in the scale of social organization" at the time of British settlement to be capable of holding title to land.

Philosophical arguments
William Blackstone defended legal fictions, observing that legislation is never free from the iron law of unintended consequences. Using the metaphor of an ancient castle, Blackstone opined:

"We inherit an old Gothic castle, erected in the days of chivalry, but fitted up for a modern inhabitant. The moated ramparts, the embattled towers, and the trophied halls, are magnificent and venerable, but useless. The interior apartments, now converted into rooms of convenience, are cheerful and commodious, though their approaches are winding and difficult."

Henry Maine, on the other hand, argued that legal fictions seem an ornate outgrowth of the law that ought to be removed by legislation. Jeremy Bentham sharply criticised the notion of legal fictions, saying that "fictions are to law what fraud is to trade."

Use in fiction
In the novel Joan and Peter (1918) by H. G. Wells, Peter's parents die in a sailing accident. As it is not known which parent dies first, a legal fiction is applied maintaining that the husband, being a man and therefore stronger, lived longer which results in the father's will determining Peter's legal guardian. Later in the novel a witness to the accident declares seeing the mother floundering some time after the father has disappeared, and so the legal fiction is overturned and the mother's will is followed, providing Peter with a new legal guardian. Wells was in error as to the English law, which actually presumes that the older person died first.

In Act II, Scene 1 of Gilbert and Sullivan's The Gondoliers, Giuseppe Palmieri (who serves jointly with his brother Marco as King of Barataria) requests that he and his brother be recognized individually, that they might receive individual portions of food as they have two independent appetites. He is turned down because the joint rule "... is a legal fiction, and legal fictions are solemn things."

In the novel Lud-in-the-Mist (1926) by Hope Mirrlees, the concept of the legal fiction as a secular substitute for spiritual mysteries and magical illusions is a central theme. Legal fictions in the novel include referring to fairy fruit, mention of which is taboo, as woven silk fabric in order to allow the law to regulate it; and declaring members of the country's Senate "dead in the eyes of the law" in order to remove them from office, since the senators serve for life.

Limitations on their use
Legal fictions derive their legitimacy from tradition and precedent, rather than formal standing as a source of law. Historically, many legal fictions were created as ad hoc remedies forged to meet a harsh or an unforeseen situation. Conventions and practices over the centuries have imparted a degree of stability both to the institution of legal fictions and to specific legal fictions (such as adoptions and corporate personhood) that have been repeatedly invoked in judicial precedents. While judiciaries retain discretion in the use of legal fictions, some general propositions regarding the appropriateness of using legal fictions might be expressed as follows:

 * A legal fiction should not be employed to defeat law or result in illegality: it has been always stressed that a legal fiction should not be employed where it would result in the violation of any legal rule or moral injunction. In Sinclair v. Brougham 1914 AC 378 the House of Lords refused to extend the juridical basis of a quasi-contract to a case of an ultra vires borrowing by a limited company, since it would sanction the evasion of the rules of public policy forbidding an ultra vires borrowing by a company. In general, if it appears that a legal fiction is being used to circumvent an existing rule, the courts are entitled to disregard that fiction and look at the real facts. The doctrine of "piercing the corporate veil" is applied under those circumstances.
 * Legal fiction should operate for the purpose for which it was created and should not be extended beyond its legitimate field.

Codified legal fictions
Some legal fictions are codified in statutory or regulatory law. Person having ordinary skill in the art is an example of such a legal fiction.

title: Legal fiction


text:
XLR

XLR may refer to:

 * XLR connector, an electrical connector commonly used in audio equipment
 * Cadillac XLR, a retractable hardtop convertible automobile
 * Megas XLR, an American animated television series
 * X-linked recessive inheritance
 * XLR-8, a roller coaster
 * XL programming language runtime
 * A321XLR, a variant of the Airbus A321neo airliner

title: XLR


text:
Candas Jane Dorsey

Candas Jane Dorsey (born November 16, 1952) is a Canadian poet and science fiction novelist who resides in her hometown of Edmonton, Alberta. Dorsey became a writer from an early age and works across genre boundaries, writing poetry, fiction, mainstream and speculative, short and long form, arts journalism and arts advocacy. Dorsey has also written television and stage scripts, magazine and newspaper articles, and reviews.

Dorsey currently teaches and holds workshops and readings. She has served on the executive board of the Writers Guild of Alberta and is a founder of SF Canada. In 1998, Dorsey received the Aurora Award.

Dorsey was editor-in-chief of The Books Collective (River, Slipstream and Tesseract Books) from 1992 through 2005.

Epitome Apartments series

 * The Adventures of Isabel: A Postmodern Mystery, By the Numbers - 2020
 * What's the Matter with Mary Jane?  - 2021
 * He Wasn’t There Again Today - 2023

title: Candas Jane Dorsey


text:
Talk:Video game console

comparison of current?
I miss comparison of consoles currently on sale from player's point of view.

Valve Steam Deck
Should the steam deck be included in this article? Does it count as a gaming console? NowInHD (talk) 17:32, 1 March 2022 (UTC)
 * No, it is a handheld computer system. In particular it is far from being a closed platform compared to consoles. --M asem (t) 17:39, 1 March 2022 (UTC)
 * Article clearly states "Video game consoles are a specialized form of a home computer geared towards video game playing" and Steam Deck is very clearly geared towards video game playing. Where in the Video Game Console definition is it stated, that it has to be a closed platform to count as one? Ashirviskas (talk) 19:44, 20 August 2022 (UTC)
 * The completly open nature of the Steam Deck makes it a "Personal Computer" (AKA a PC) + """ SYSTEM """ ( Meaning everything needed to make it funtion is incuded. )
 * Microsoft is the only one to call the there ""Video game system"" a console.
 * A Console is nothing more than an interface to a computer system ( keyboard, mouse, controller, pen, ....) 24.168.43.223 (talk) 19:50, 4 October 2022 (UTC)
 * This Article Lists the steam deck
 * https://en.wikipedia.org/wiki/Handheld_game_console#2020s 23.24.41.217 (talk) 15:49, 1 December 2022 (UTC)
 * We don't use Wikipedia as its own source for obvious reasons M asem (t) 16:08, 1 December 2022 (UTC)

Wiki Education assignment: The Editing Process
— Assignment last updated by Ali01225 (talk) 19:10, 20 October 2022 (UTC)

title: Talk:Video game console


text:
Monotonicity criterion

The positive response,   monotonicity, or nonperversity criterion is a principle of social choice theory that says that increasing a candidate's ranking or rating should not cause them to lose. Positive response rules out cases where a candidate loses an election as a result of receiving too much support from voters (i.e. being "too popular to win"); rules that violate positive response are called perverse.

Systems that violate positive response (such as instant-runoff and the two-round system) can create situations where a voter's ballot has a reversed effect on the election, making it "less than worthless". This runs counter to the basic principle that increasing an option's popularity in a democratic election should only improve the chances of that option winning; as a result, German courts have previously struck down nonmonotonic systems for violating the right to equal and direct suffrage.

Most voting systems (including Borda and all common tournament solutions) satisfy positive response, as do all commonly-used rated voting methods (including approval, score, and their proportional counterparts).

However, the criterion is violated by instant-runoff voting, the single transferable vote, and Hamilton's apportionment method.

The participation criterion is a closely-related, but different, concept. While positive responsiveness deals with a voter changing their opinion (or vote), participation deals with situations where a voter choosing to cast a ballot can have a reversed effect on the election.

Runoff voting
Runoff-based voting systems, such as ranked choice voting (instant-runoff) fail the monotonicity criterion. A notable example is the 2009 Burlington mayoral election, the United States' second instant-runoff election in the modern era, where Bob Kiss won the election as a result of 750 ballots ranking him in last place.

An example with three parties (Top, Center, Bottom) is shown below. In this scenario, the Bottom party initially loses. However, they are elected after running an unsuccessful campaign and adopting an unpopular platform, which pushes their supporters away from the party and into the Top party. This election is an example of a center-squeeze, a class of elections where instant-runoff and plurality have difficulties electing the majority-preferred candidate, because the first-round vote is split between an extremist and a moderate. Here, the loss of support for Bottom policies makes the Top party more popular, allowing it to defeat the Center party in the first round.

A famous example of a monotonicity failure is the 2022 Alaska at-large special election.

Quota rules
Proportional representation systems using largest remainders for apportionment do not pass the monotonicity criterion. This happened in the 2005 German federal election, when CDU voters in Dresden were instructed to vote for the FDP, a strategy that allowed the party an additional seat. As a result, the Federal Constitutional Court ruled that negative voting weights violate the German constitution's guarantee of equal and direct suffrage.

Frequency of violations
For electoral methods failing positive value, the frequency of monotonicity violations will depend on the electoral method, the candidates, and the distribution of outcomes. Negative voting weights tend to be most common with instant-runoff, with what some researchers have described as an "unacceptably high" frequency.

Theoretical models
Results using the impartial culture model estimate about 15% of elections with 3 candidates; however, the true probability may be much higher, especially when restricting observation to close elections. For moderate numbers of candidates, the probability of a monotonicity failure quickly approaches 100%.

A 2013 study using a 2D spatial model with various voter distributions estimated at least 15% of IRV elections are nonmonotonic in the best-case scenario (when only three candidates run). The researchers concluded that "three-way competitive races will exhibit unacceptably frequent monotonicity failures" and "In light of these results, those seeking to implement a fairer multi-candidate election system should be wary of adopting IRV."

Alaska 2022
Alaska's first-ever instant-runoff election resulted in negative vote weights for many Republican supporters of Sarah Palin, who could have defeated Mary Peltola by placing her first on their ballots.

Burlington, Vermont
In Burlington's second IRV election, incumbent Bob Kiss was re-elected, despite losing in a head-to-head matchup with Democrat Andy Montroll (the Condorcet winner). However, if Kiss had gained more support from Wright voters, Kiss would have lost.

Survey of nonmonotonic elections
A survey of 185 American instant-runoff elections where no candidate was ranked first by a majority of voters found five additional elections containing monotonicity failures.

2005 German Election in Dresden
A negative voting weight event famously resulted in the abolition of Hamilton's method for apportionment in Germany after the 2005 federal election. CDU voters in Dresden were instructed to strategically vote for the FDP, a strategy that allowed the party to earn an additional seat, causing substantial controversy. As a result, the Federal Constitutional Court ruled that negative voting weights violate the German constitution's guarantee of equal and direct suffrage.

title: Monotonicity criterion


text:
Balanced audio

Balanced audio is a method of interconnecting audio equipment using balanced interfaces. This type of connection is very important in sound recording and production because it allows the use of long cables while reducing susceptibility to external noise caused by electromagnetic interference. The balanced interface guarantees that induced noise appears as common-mode voltages at the receiver which can be rejected by a differential device.

Balanced connections typically use shielded twisted-pair cable and three-conductor connectors. The connectors are usually three-pin XLR or 1/4 in TRS phone connectors. When used in this manner, each cable carries one channel, therefore stereo audio (for example) would require two of them.

A common misconception is that balanced audio requires the signal source to deliver equal waveforms of opposite polarity to the two signal conductors of the balanced line. However, many balanced devices actively drive only one side of the line, but do so at an impedance that is equal to the impedance of the non-driven side of the line. This impedance balance permits the balanced line receiver (input stage of the next device) to reject common-mode signals introduced to the two conductors by electromagnetic coupling.

Applications
Many microphones operate at low voltage levels and some with high output impedance (hi-Z), which makes long microphone cables especially susceptible to electromagnetic interference. Microphone interconnections are therefore a common application for a balanced interconnection, which allows the receiver to reject most of this induced noise. If the power amplifiers of a public address system are located at any distance from the mixing console, it is also normal to use balanced lines for the signal paths from the mixer to these amplifiers. Many other components, such as graphic equalizers and effects units, have balanced inputs and outputs to allow this. In recording and for short cable runs in general, a compromise is necessary between the noise reduction given by balanced lines and the cost introduced by the extra circuitry they require.

Some devices, usually with a transformer output, provide a balanced output that is "floating" with respect to ground; the impedance to ground from each side of the output is high. More commonly, devices drive one or both sides of the balanced interface with a signal referenced to ground. When one side is not driven, care is taken to assure that the impedance to ground is equal to the impedance of the driven side.

Interference reduction
Balanced audio connections use a number of techniques to reduce noise.

A typical balanced cable contains two identical wires, which are twisted together and then wrapped with a third conductor (foil or braid) that acts as a shield. The two wires form a circuit that can carry an audio signal.

The term balanced comes from the method of balancing the impedance of each wire in the circuit; the line and all circuits directly connected to it (such as the driver and receiver) must have identical impedances with respect to some reference point. This means that much of the electromagnetic interference will induce an equal noise voltage in each wire. Since the differential device at the receiving end only responds to the difference in voltage between the two signal lines, noise that is identical on both wires is rejected. This method can be implemented with a differential amplifier. A transformer may also be used instead of an active input stage.

A twisted pair makes the loop area between the conductors as small as possible, and ensures that a magnetic field that passes equally through adjacent loops will induce equal levels of noise on both lines, which is canceled out by the differential device in the receiver. If the noise source is extremely close to the cable, then it is possible it will be induced on one of the lines more than the other, and it will not be canceled as well, but canceling will still occur to the extent of the amount of noise that is equal on both lines.

The separate shield that is commonly provided in a balanced audio cable also yields a noise rejection advantage over an unbalanced two-conductor arrangement (such as used in typical home stereos) where the shield must also act as the signal return wire. Therefore, any noise currents induced into a balanced audio shield will not be directly modulated onto the signal, whereas in a two-conductor system they will be. This also prevents ground loop problems, by separating the shield/chassis from signal ground.

Differential signaling
Signals are often transmitted over balanced connections using the differential mode, meaning the wires carry signals that are equal in magnitude but of opposite polarity to each other (for instance, in an XLR connector, pin 2 carries the signal with normal polarity, and pin 3 carries an inverted version of the same signal). Despite popular belief, this arrangement is not necessary for noise rejection. As long as the impedances are balanced, noise will couple equally into the two wires (and be rejected by a differential amplifier), regardless of the signal that is present on them. A simple method of driving a balanced line is to inject the signal into the "hot" wire through a known source impedance, and connect the "cold" wire to the signal's local ground reference through an identical impedance. Due to common misconceptions about differential signalling, this is often referred to as a quasi-balanced or impedance-balanced output, though it is, in fact, fully balanced and will reject common-mode interference.

However, there are some minor benefits to driving the line with a fully differential output:
 * Though the signal level would not be changed due to nominal level standardization, the maximum output from the differential drivers is twice as much, giving 6 dB extra headroom.
 * Increasing cable capacitance over long cable runs decreases the signal level at which high frequencies are attenuated. If each wire carries half the signal voltage swing as in fully differential outputs then longer cable runs can be used without the loss of high frequencies.
 * Noise that is correlated between the two amps (from imperfect power supply rejection, for instance), would be cancelled out.
 * At higher frequencies, the output impedance of the output amplifier can change, resulting in a small imbalance. When driven in differential mode by two identical amplifiers, this impedance change will be the same for both lines, and thus cancelled out.

Internally balanced audio design
Professional audio products (recording, public address, etc.) generally provide balanced inputs and outputs, typically via XLR or TRS phone connectors. However, in most cases, the internal circuitry is entirely unbalanced.

A small number of audio products have been designed with an entirely balanced signal path from input to output; the circuitry maintains its impedance balance throughout the device. This design is achieved by providing identical (mirrored) internal signal paths for both the "hot" and "cold" conductors. In critical applications, a 100% balanced circuit design can offer better signal integrity by avoiding the extra amplifier stages or transformers required for front-end unbalancing and back-end rebalancing.

Connectors
Three-pin XLR connectors and quarter-inch (¼" or 6.35mm) TRS phone connectors are commonly used for balanced audio interfaces. Many jacks are now designed to take either XLR or TRS phone plugs. Equipment intended for long-term installation sometimes uses terminal strips or Euroblock connectors. Some balanced headphone connections also use a Pentaconn 4.4mm TRRRS connector.

With XLR connectors, pins 1, 2, and 3 are usually used for the shield (ideally connected to the chassis) and the two signal wires, respectively. (The phrase "ground, live, return", corresponding to "X, L, R", is often offered as a memory aid, although the second signal wire is not a "return" in the case of differential signaling) On TRS phone plugs, the tip is signal/non-inverting, the ring is return/inverting, and the sleeve is chassis ground.

If a stereophonic or other binaural signal is plugged into such a jack, one channel (usually the right) will be subtracted from the other (usually the left), leaving an unlistenable L − R (left minus right) signal instead of normal monophonic L + R (left plus right). Reversing the polarity at any other point in a balanced audio system will also result in this effect at some point when it is later mixed-down with its other channel.

Telephone lines also carry audio through balanced circuitry, though this is generally now limited to the local loop. It is called this because the two wires form a balanced loop through which both sides of the telephone call travel. As telephones require DC power to operate and to allow simple on/off hook detection, extra circuitry was developed where one signal wire is fed from the exchange power bus, typically −50 volts, and the other grounded, both via equal value inductors which have about 400 ohms DC resistance, to avoid short-circuiting the wanted AC signal and to maintain impedance balance.

Digital audio connections in professional environments are also frequently balanced, normally following the AES3 (AES/EBU) standard. This uses XLR connectors and twisted-pair cable with 110-ohm impedance. By contrast, the coaxial S/PDIF interface commonly seen on consumer equipment is unbalanced.

Converters
Balanced and unbalanced circuits can be interfaced by the use of a balun, often through a DI unit (also called a "DI box" or "direct box").

As a last resort a balanced audio line can be fed into an unbalanced input and vice versa as long as the electronic design used for the output stage is known. In the case of balanced output to unbalanced input, the negative output can be tied to ground, but in certain cases the negative output should be left disconnected.

title: Balanced audio


text:
Phone connector (audio)

A phone connector is a family of cylindrically-shaped electrical connectors primarily for analog audio signals. Invented in the late 19th century for telephone switchboards, the phone connector remains in use for interfacing wired audio equipment, such as headphones, speakers, microphones, mixing consoles, and electronic musical instruments (e.g. electric guitars, keyboards, and effects units). A male connector (a plug), is mated into a female connector (a socket), though other terminology is used.

Plugs have 2 to 5 electrical contacts. The tip contact is indented with a groove. The sleeve contact is nearest the (conductive or insulated) handle. Contacts are insulated from each other by a band of non-conductive material. Between the tip and sleeve are 0 to 3 ring contacts. Since phone connectors have many uses, it is common to simply name the connector according its number of rings:

The sleeve is usually a common ground reference voltage or return current for signals in the tip and any rings. Thus, the number of transmittable signals is less than the number of contacts.

The outside diameter of the sleeve is 6.35 mm for full-sized connectors, 3.5 mm for "mini" connectors, and only 2.5 mm for "sub-mini" connectors. Rings are typically the same diameter as the sleeve.

Other terms
The 1902 International Library of Technology simply uses jack for the female and plug for the male connector. The 1989 Sound Reinforcement Handbook uses phone jack for the female and phone plug for the male connector. Robert McLeish, who worked at the BBC, uses jack or jack socket for the female and jack plug for the male connector in his 2005 book Radio Production. The American Society of Mechanical Engineers, as of 2007, says the more fixed electrical connector is the jack, while the less fixed connector is the plug, without regard to the gender of the connector contacts. The Institute of Electrical and Electronics Engineers in 1975 also made a standard that was withdrawn in 1997.

The intended application for a phone connector has also resulted in names such as audio jack, headphone jack, stereo plug, microphone jack, aux input, etc. Among audio engineers, the connector may often simply be called a quarter-inch to distinguish it from XLR, another frequently-used audio connector. These naming variations are also used for the 3.5 mm connectors, which have been called mini-phone, mini-stereo, mini jack, etc.

RCA connectors are differently-shaped, but confusingly are similarly-named as phono plugs and phono jacks (or in the UK, phono sockets). 3.5 mm connectors are sometimes—counter to the connector manufacturers' nomenclature —referred to as mini phonos.

Confusion also arises because phone jack and phone plug may sometimes refer to the RJ11 and various older telephone sockets and plugs that connect wired telephones to wall outlets.

Historical development
The original 1/4 in version descends from as early as 1877 in Boston when the first telephone switchboard was installed or 1878, when an early switchboard was used for the first commercial manual telephone exchange in New Haven created by George W. Coy. Charles E. Scribner filed a patent in 1878 to facilitate switchboard operation using his spring-jack switch. In it, a conductive lever pushed by a spring is normally connected to one contact. But when a cable with a conductive plug is inserted into a hole and makes contact with that lever, the lever pivots and breaks its normal connection. The receptacle was called a jack-knife because of its resemblance to a pocket clasp-knife. This is said to be the origin of calling the receptacle a jack. Scribner filed a patent in 1880 which removes the lever and resembles the modern connector and made improvements to switchboard design in subsequent patents filed in 1882.

Henry P. Clausen filed a patent in 1901 for improved construction of the telephone switchboard-plug with today's $1/4$ inch TS form still used on audio equipment.

Western Electric was the manufacturing arm of the Bell System, and thus originated or refined most of the engineering designs, including the telephone jacks and plugs which were later adopted by other industries, including the US military.

By 1907, Western Electric had designed a number of models for different purposes, including: By 1950, the two main plug designs were:

 * WE-309 (compatible with $1/4$-inch jacks, such as 246 jack), for use on high-density jack panels such as the 608A
 * WE-310 (compatible with $3/16$-inch jacks, such as the 242)

Several modern designs have descended from those earlier versions:

 * B-Gauge standard BPO316 (not compatible with EIA RS-453)
 * EIA RS-453: Dimensional, Mechanical and Electrical Characteristics Defining Phone Plugs & Jacks standard of 0.206 in diameter, also found in IEC 60603-11:1992 Connectors for frequencies below 3 MHz for use with printed boards – Part 11: Detail specification for concentric connectors (dimensions for free connectors and fixed connectors).

Military variants
U.S. military versions of the Western Electric plugs were initially specified in Amendment No.1, MIL-P-642, and included:

 * M642/1-1
 * M642/1-2
 * M642/2-1
 * M642/2-2
 * M642/4-1
 * M642/4-2
 * MIL-P-642/2, also known as PJ-051. (Similar to Western Electric WE-310, and thus not compatible with EIA RS-453)
 * MIL-P-642/5A: Plug, Telephone (TYPE PJ-068) and Accessory Screws (1973), and MIL-DTL-642F: Plugs, Telephone, and Accessory Screws (2015), with 0.206 in diameter, also known by the earlier Signal Corps PL-68 designation. These are commonly used as the microphone jack for aviation radios, and on Collins S-line and many Drake amateur radios. MIL-DTL-642F states, "This specification covers telephone plugs used in telephone (including telephone switchboard consoles), telegraph, and teletype circuits, and for connecting headsets, handsets, and microphones into communications circuits."

Miniature size
The 3.5 mm or miniature size was originally designed in the 1950s as two-conductor connectors for earpieces on transistor radios, and remains a standard still used today. This roughly half-sized version of the original, popularized by the Sony EFM-117J radio (released in 1964),  is still commonly used in portable applications and has a length of 14 mm. The three-conductor version became very popular with its application on the Walkman in 1979, as unlike earlier transistor radios, these devices had no speaker of their own; the usual way to listen to them was to plug in headphones. There is also an EIA standard for 0.141-inch miniature phone jacks.

The 2.5 mm or sub-miniature sizes were similarly popularized on small portable electronics. They often appeared next to a 3.5 mm microphone jack for a remote control on-off switch on early portable tape recorders; the microphone provided with such machines had the on-off switch and used a two-pronged connector with both the 3.5 and 2.5 mm plugs. They were also used for low-voltage DC power input from wall adapters. In the latter role, they were soon replaced by coaxial DC power connectors. 2.5 mm phone jacks have also been used as headset jacks on mobile telephones (see ).

The $1/4$ in and $1/8$ in sizes, approximately 3.5 mm and 2.5 mm respectively in mm, though those dimensions are only approximations. All sizes are now readily available in two-conductor (unbalanced mono) and three-conductor (balanced mono or unbalanced stereo) versions.

Four-conductor versions of the 3.5 mm plug and jack are used for certain applications. A four-conductor version is often used in compact camcorders and portable media players, providing stereo sound and composite analog video. It is also used for a combination of stereo audio, a microphone, and controlling media playback, calls, volume and/or a virtual assistant on some laptop computers and most mobile phones, and some handheld amateur radio transceivers from Yaesu. Some headphone amplifiers have used it to connect balanced stereo headphones, which require two conductors per audio channel as the channels do not share a common ground.

Broadcast usage
By the 1940s, broadcast radio stations were using Western Electric Code No. 103 plugs and matching jacks for patching audio throughout studios. This connector was used because of its use in AT&T's Long Line circuits for the distribution of audio programs over the radio networks' leased telephone lines. Because of the large amount of space these patch panels required, the industry began switching to 3-conductor plugs and jacks in the late 1940s, using the WE Type 291 plug with WE type 239 jacks. The type 291 plug was used instead of the standard type 110 switchboard plug because the location of the large bulb shape on this TRS plug would have resulted in both audio signal connections being shorted together for a brief moment while the plug was being inserted and removed. The Type 291 plug avoids this by having a shorter tip.

Patch bay connectors
Professional audio and the telecommunication industry use a 0.173 in diameter plug, associated with trademarked names including Bantam, TT, Tini-Telephone, and Tini-Tel. They are not compatible with standard EIA RS-453/IEC 60603-11 $1/10$-inch jacks. In addition to a slightly smaller diameter, they have a slightly different geometry. The three-conductor TRS versions are capable of handling balanced line signals and are used in professional audio installations. Though unable to handle as much power, and less reliable than a 6.35 mm jack, Bantam connectors are used for mixing console and outboard patchbays in recording studio and live sound applications, where large numbers of patch points are needed in a limited space. The slightly different shape of Bantam plugs is also less likely to cause shorting as they are plugged in.

Less common

A two-pin version, known to the telecom industry as a "310 connector", consists of two $1/4$-inch phone plugs at a centre spacing of 5/8 in. The socket versions of these can be used with normal phone plugs provided the plug bodies are not too large, but the plug version will only mate with two sockets at $1/4$ inches centre spacing, or with line sockets, again with sufficiently small bodies. These connectors are still used today in telephone company central offices on "DSX" patch panels for DS1 circuits. A similar type of 3.5 mm connector is often used in the armrests of older aircraft, as part of the on-board in-flight entertainment system. Plugging a stereo plug into one of the two mono jacks typically results in the audio coming into only one ear. Adapters are available.

A short-barrelled version of the phone plug was used for 20th-century high-impedance mono headphones, and in particular those used in World War II aircraft. These have become rare. It is physically possible to use a normal plug in a short socket, but a short plug will neither lock into a normal socket nor complete the tip circuit.

Less commonly used sizes, both diameters and lengths, are also available from some manufacturers, and are used when it is desired to restrict the availability of matching connectors, such as 0.210 in inside diameter jacks for fire safety communication in public buildings.

Decline
Digital audio is now common and may be transmitted via USB sound cards, USB headphones, Bluetooth, display connectors with integrated sound (e.g. DisplayPort and HDMI). Digital devices may also have internal speakers and mics. Thus the phone connector is sometimes considered redundant and a waste of space, particularly on thinner mobile devices. And while low-profile surface-mount sockets waterproofed up to 1 meter exist, removing the socket entirely facilitates waterproofing.

Chinese phone manufacturers were early in not using a phone socket: first with Oppo's Finder in July 2012 (which came packaged with micro-USB headphones and supported Bluetooth headphones), followed by Vivo's X5Max in 2014 and LeEco in April 2016 and Lenovo's Moto Z in September 2016. Apple's September 2016 announcement of the iPhone 7 was initially mocked for removing the socket by other manufacturers like Samsung and Google who eventually followed suit. The socket is also not present in some tablets and thin laptops (e.g. Lenovo Duet Chromebook and Asus ZenBook 13 in 2020 ).

Aviation and US military connectors

The US military uses a variety of phone connectors including $5/8$-inch (0.281-inch, 7.14 mm) and $9/32$-inch (0.25 inch, 6.35 mm) diameter plugs.

Commercial and general aviation (GA) civil aircraft headsets often use a pair of phone connectors. A standard $1/4$-inch (6.3 mm) 2 or 3-conductor plug, type PJ-055, is used for headphones. For the microphone, a smaller $1/4$-inch (0.206 inch / 5.23 mm) diameter 3-conductor plug, type PJ-068, is used.

Military aircraft and civil helicopters have another type termed the U-174/U (Nexus TP-101), also known as U-93A/U (Nexus TP-102) and Nexus TP-120. These are also known as US NATO plugs. These have a 0.281 in diameter shaft with four conductors, allowing two for the headphones, and two for the microphone. Also used is the U-384/U (Nexus TP-105), which has the same diameter as the U-174/U but is slightly longer and has 5 conductors instead of 4.

There is a confusingly similar four-conductor British connector, Type 671 (10H/18575), with a slightly larger diameter of 7.57 mm used for headsets in many UK military aircraft and often referred to as a UK NATO or European NATO connector.

General use

In the most common arrangement, consistent with the original intention of the design, the male plug is connected to a cable, and the female socket is mounted in a piece of equipment. A considerable variety of line plugs and panel sockets is available, including plugs suiting various cable sizes, right-angle plugs, and both plugs and sockets in a variety of price ranges and with current capacities up to 15 amperes for certain heavy-duty $3/16$ in versions intended for loudspeaker connections.

Common uses of phone plugs and their matching sockets include:

 * Headphone and earphone jacks on a wide range of equipment. 6.35 mm ($1/4$ in) plugs are common on home and professional component equipment, while 3.5 mm plugs are nearly universal for portable audio equipment and headphones. 2.5 mm plugs are not as common, but are used on communication equipment such as cordless phones, mobile phones, and two-way radios, especially in the earliest years of the 21st century before the 3.5 mm became standard on mobile phones. The use of headphone jacks in smartphones is declining in favor of USB-C connectors and wireless Bluetooth solutions.
 * Consumer electronics devices such as digital cameras, camcorders, and portable DVD players use 3.5 mm connectors for composite video and audio output. Typically, a TRS connection is used for mono unbalanced audio plus video, and a TRRS connection for stereo unbalanced audio plus analog video. Cables designed for this use are often terminated with RCA connectors on the other end. A combined video/audio jack is also present on some computers; several generations of the Raspberry Pi have analog audio and video from the same jack, and Sony also used this style of connection as the TV-out on some models of Vaio laptop.
 * Hands-free sets and headsets often use 3.5 mm or 2.5 mm connectors. TRS connectors are used for mono audio out and an unbalanced microphone (with a shared ground). Four-conductor TRRS phone connectors add an additional audio channel for stereo output. TRRS connectors used for this purpose are sometimes interoperable with TRS connectors, depending on how the contacts are used.
 * Microphone inputs on tape and cassette recorders, sometimes with remote control switching on the ring, on early, monaural cassette recorders mostly a dual-pin version consisting of a 3.5 mm TS for the microphone and a 2.5 mm TS for remote control which switches the recorder's power supply.
 * Patching points (insert points) on a wide range of equipment. An unusual example is the Enigma machine, which featured a plugboard as part of its encryption system.

Computer sound
Any number of 3.5 mm sockets for input and output may be found on personal computers, either from integrated sound hardware common on motherboards or from insertable sound cards. The 1999 PC System Design Guide's color code for 3.5 mm TRS sockets is common, which assigns pink for microphone, light blue for line in, and lime for line level. AC'97 and its 2004 successor Intel High Definition Audio have been widely adopted specifications that, while not mandating physical sockets, do provide specifications for a front panel connector with pin assignments for two ports with jack detection. Front panels commonly have a stereo output socket for headphones and (slightly less commonly) a stereo input socket for a mic. The back panel may have additional sockets, most commonly for line out, mic, line in, and less commonly for multiple surround sound outs. Laptops and tablets tend to have fewer sockets than desktops due to size constraints.

Microphone power
Some computers include a 3.5 mm TRS socket for mono microphone that delivers a 5 V bias voltage on the ring to power an electret microphone's integrated buffer amplifier, though details depend on the manufacturer. The Apple PlainTalk microphone socket is a historical variant that accepts either a 3.5 mm line input or an elongated 3.5 mm TRS plug whose tip carries the amplifier's power.

TRRS headset sockets
Some newer computers, especially laptops, have 3.5 mm TRRS headset sockets, which are compatible with phone headsets and may be distinguished by a headset icon instead of the usual headphones or microphone icons. These are particularly used for voice over IP.

Surround sound
Sound cards that output 5.1 surround sound have three sockets to accommodate six channels: front left and right; surround left and right; and center and subwoofer. 6.1 and 7.1 channel sound cards from Creative Labs, however, use a single three-conductor socket (for the front speakers) and two four-conductor sockets. This is to accommodate rear-center (6.1) or rear left and right (7.1) channels without the need for additional sockets on the sound card.

Combined TRS and TOSLINK
Some portable computers have a combined 3.5 mm TRS/TOSLINK jack, supporting stereo audio output using either a TRS connector or TOSLINK (stereo or 5.1 Dolby Digital/DTS) digital output using a suitable optical adapter. Most iMac computers have this digital/analog combo output feature as standard, with early MacBooks having two ports, one for analog/digital audio input and the other for output. Support for input was dropped on various later models

Compatibility for different numbers of rings
The original application for the 6.35 mm ($1/4$ in) phone jack was in manual telephone exchanges. Many different configurations of these phone plugs were used, some accommodating five or more conductors, with several tip profiles. Of these many varieties, only the two-conductor version with a rounded tip profile was compatible between different manufacturers, and this was the design that was at first adopted for use with microphones, electric guitars, headphones, loudspeakers, and other audio equipment.

When a three-conductor version of the 6.35 mm plug was introduced for use with stereo headphones, it was given a sharper tip profile to make it possible to manufacture jacks that would accept only stereo plugs, to avoid short-circuiting the right channel of the amplifier. This attempt has long been abandoned, and now the convention is that all plugs fit all sockets of the same size, regardless of whether they are balanced or unbalanced, mono or stereo. Most 6.35 mm plugs, mono or stereo, now have the profile of the original stereo plug, although a few rounded mono plugs are still produced. The profiles of stereo miniature and sub-miniature plugs have always been identical to the mono plugs of the same size.

The results of this physical compatibility are:

Equipment aware of this possible shorting allows, for instance:
 * If a 2-conductor plug is inserted into a 3-conductor socket, then the socket's ring is shorted to ground, thus any signal sent from that socket's ring is lost. Equipment not designed for this short might, for instance, damage an audio amplifier channel.
 * If a 3-conductor plug is connected to a 2-conductor socket, normally the result is to leave the ring of the plug unconnected. This open circuit is potentially dangerous to equipment using vacuum tubes, but most solid-state devices will tolerate an open condition.

Some devices for an even higher number of rings might possibly be backwards-compatible with an opposite-gendered device with fewer rings, or may cause damage. For example, 3.5 mm TRRS sockets that accept TRRS headsets (stereo headphones with a mic) are often compatible with standard TRS stereo headphones, whereby the contact that expects a mic signal will instead simply become shorted to ground and thus will provide a zero signal. Conversely, those TRRS headsets can plug into TRS sockets, in which case its speakers may still work even though its mic won't work (the mic's signal contact will be disconnected).
 * Mono equipment receiving stereo output will simply use the left (tip) channel as the mono input signal and lose the right (ring) channel of the stereo audio.
 * The positive (tip) component of a balanced signal will be received, though without the full benefits of balanced audio, since the signal's negative (ring) component will be lost.

Because of a lack of standardization in the past regarding the dimensions (length) given to the ring conductor and the insulating portions on either side of it in 6.35 mm ($1/4$ in) phone connectors and the width of the conductors in different brands and generations of sockets, there are occasional issues with compatibility between differing brands of plug and socket. This can result in a contact in the socket bridging (shorting) the ring and sleeve contacts on a phone connector.

Video

Equipment requiring video with stereo audio input or output sometimes uses 3.5 mm TRRS connectors. Two incompatible variants exist, of 15 mm and 17 mm length, and using the wrong variant may either simply not work, or could cause physical damage.

Attempting to fully insert the longer (17 mm) plug into a receptacle designed for the shorter (15 mm) plug may damage the receptacle, and may damage any electronics located immediately behind the receptacle. However, partially inserting the plug will work as the tip/ring/ring distances are the same for both variants.

A shorter plug in a socket designed for the longer connector may not be retained firmly and may result in wrong signal routing or a short circuit inside the equipment (e.g. the plug tip may cause the contacts inside the receptacle – tip/ring 1, etc. – to short together).

The shorter 15 mm TRRS variant is more common and physically compatible with standard 3.5 mm TRS and TS connectors.

Recording equipment

Many small video cameras, laptops, recorders and other consumer devices use a 3.5 mm microphone connector for attaching a microphone to the system. These fall into three categories:
 * Devices that use an unpowered microphone: usually a cheap dynamic or piezoelectric microphone. The microphone generates its own voltage and needs no power.
 * Devices that use a self-powered microphone: usually a condenser microphone with an internal battery-powered amplifier.
 * Devices that use a plug-in powered microphone: an electret microphone containing an internal FET amplifier. These provide a good quality signal in a very small microphone. However, the internal FET needs a DC power supply, which is provided as a bias voltage for an internal preamp transistor. Plug-in power is supplied on the same line as the audio signal, using an RC filter. The DC bias voltage supplies the FET amplifier (at a low current), while the capacitor decouples the DC supply from the AC input to the recorder. Typically, V=1.5 V, R=1 kΩ, C=47 μF. If a recorder provides plug-in power, and the microphone does not need it, everything will usually work well. In the converse case (recorder provides no power; microphone needs power), no sound will be recorded.

Mobile devices

Three- or four-conductor (TRS or TRRS) 2.5 mm and 3.5 mm sockets were common on older cell phones and smartphones respectively, providing mono (three-conductor) or stereo (four-conductor) sound and a microphone input, together with signaling (e.g., push a button to answer a call). These are used both for handsfree headsets and for stereo headphones.

3.5 mm TRRS (stereo-plus-mic) sockets became particularly common on smartphones, and have been used by Nokia and others since 2006, and as mentioned in the compatibility section, they are often compatible with standard 3.5 mm stereo headphones. Many computers, especially laptops, also include a TRRS headset socket compatible with the headsets intended for smartphones.

The four conductors of a TRRS connector are assigned to different purposes by different manufacturers. Any 3.5 mm plug can be plugged mechanically into any socket, but many combinations are electrically incompatible. For example, plugging TRRS headphones into a TRS headset socket, a TRS headset into a TRRS socket, or plugging TRRS headphones from one manufacturer into a TRRS socket from another may not function correctly, or at all. Mono audio will usually work, but stereo audio or the microphone may not work, or the pause/play controls may be inactive, as is common when trying to use headphones with controls for iPhones on an Android device, or vice versa.

TRRS standards
Two different forms are frequently found. Both place left audio on the tip and right audio on the first ring, same as stereo connectors. They differ in the placement of the microphone and return contacts.

The OMTP standard places the ground return on the sleeve and the microphone on the second ring. It has been accepted as a national Chinese standard YDT 1885–2009. In the West, it is mostly used on older devices, such as older Nokia mobiles, older Samsung smartphones, and some Sony Ericsson phones. It is widely used in products meant for the Chinese market. Headsets using this wiring are sometimes indicated by black plastic separators between the rings.

The CTIA/AHJ standard reverses these contacts, putting the microphone on the sleeve. It is used by Apple's iPhone line until the 6S and SE (1st). In the West, these products made it the de facto TRRS standard. It is now used by HTC devices, recent Samsung, Nokia, and Sony phones, among others. It has the disadvantage that the microphone gets shorted to ground if the device has a metal body and the sleeve has a flange, touching the body. Headsets using this wiring are sometimes indicated by white plastic separators between the rings.

If a CTIA headset is connected to an OMTP device, the missing ground effectively connects the speakers in series, out-of-phase. This removes the singer's voice on typical popular music recordings, which place the singers in the center. If the main microphone button is held down, shorting across the microphone and restoring ground, the correct sound may be audible.

The 4-pole 3.5 mm connector is defined by the Japanese standard JEITA/EIAJ RC-5325A, "4-Pole miniature concentric plugs and jacks", originally published in 1993. 3-pole 3.5 mm TRS connectors are defined in JIS C 6560. See also JIS C 5401 and IEC 60130-8.

Apple's iPod Shuffle 2G reuses its TRRS socket not just for audio but also for charging and syncing over USB when docked.

Interoperability
The USB Type-C Cable and Connector Specification specifies a mapping from a USB-C jack to a 4-pole TRRS jack, for the use of headsets, and supports both CTIA and OMTP (YD/T 1885–2009) modes. Some devices transparently handle many jack standards, and there are hardware implementations of this available as components. This is accomplished in some cases by applying a voltage to the sleeve and second ring to detect the wiring. The last two conductors may then be switched to allow a device made to one standard to be used with a headset made to the other.

TRRRS standards
A TRRRS standard for 3.5 mm connectors was developed by ITU-T. The standard, called P.382 (formerly P.MMIC), outlines technical requirements and test methods for a 5-conductor socket and plug configuration. Compared to the TRRS standard, TRRRS provides one extra conductor that can be used for connecting a second microphone or providing power to or from the audio accessory.

P.382 requires compliant sockets and plugs to be backward compatible with legacy TRRS and TRS connectors. Therefore, P.382-compliant TRRRS connectors should allow for seamless integration when used on new products. TRRRS connectors enable the following audio applications: active noise canceling, binaural recording and others, where dual analog microphone lines can be directly connected to a host device. It was commonly found on Sony phones starting with the Xperia Z1-XZ1 and Xperia 1 II.

Another TRRRS standard for 4.4 mm connectors following JEITA RC-8141C was introduced in 2015 and is used for balanced audio connections, in particular for headphone cables. This connector is often called a Pentaconn connector following the brand name of Nippon DICS (NDICS). It is used by some Sony products like the M1Z Walkman of their Signature series and by some Sennheiser products like the HD 820 headphone or the HDV 820 DAC headphone amplifier.

Switch contacts
Panel-mounted jacks may include switch contacts. Most commonly, a mono jack is provided with one normally closed (NC) contact, which is connected to the tip (live) connection when no plug is in the socket, and disconnected when a plug is inserted. Stereo sockets commonly provide two such NC contacts, one for the tip (left channel) and one for the ring or collar (right channel). Some jacks also have such a connection on the sleeve. As this contact is usually ground, it is not much use for signal switching but could be used to indicate to electronic circuitry that the jack is in use. Less commonly, jacks may feature normally open (NO) or change-over contacts or the switch contacts may be isolated from the connector signals.

The original purpose of these contacts was for switching in telephone exchanges, for which there were many patterns. Two sets of change-over contacts, isolated from the connector contacts, were common. The more recent pattern of one NC contact for each signal path, internally attached to the connector contact, stems from their use as headphone jacks. In many amplifiers and equipment containing them, such as electronic organs, a headphone jack is provided that disconnects the loudspeakers when in use. This is done by means of these switch contacts. In other equipment, a dummy load is provided when the headphones are not connected. This is also easily provided by means of these NC contacts.

Other uses for these contacts have been found. One is to interrupt a signal path in a mixing console to insert an effects processor. This is accomplished by using one NC contact of a stereo jack to connect the tip and ring together to affect a bypass when no plug is inserted. A similar arrangement is used in patch panels for normalization (see ).

Where a 3.5 mm or 2.5 mm jack is used as a DC power inlet connector, a switch contact may be used to disconnect an internal battery whenever an external power supply is connected, to prevent incorrect recharging of the battery.

To eliminate the need for a separate power switch, a standard stereo jack is used on most battery-powered guitar effects pedals. The internal battery has its negative terminal wired to the sleeve contact of the jack. When the user plugs in a two-conductor (mono) plug, the resulting short circuit between the sleeve and ring connects an internal battery to the unit's circuitry, ensuring that it powers up or down automatically whenever a signal lead is inserted or removed.

Design

The connector assembly is usually made by one or more hollow and one solid pin. The jack is then assembled with pins separated by an insulating material.

Connectors that are tarnished, or that were not manufactured within tight tolerances, are prone to cause poor connections. Depending upon the surface material of the connectors, tarnished ones can be cleaned with a burnishing agent (for solid brass contacts typical) or contact cleaner (for plated contacts).

Audio signals

 * Notes:

Balanced audio
When a phone connector is used to make a balanced connection, the two active conductors are used for differential versions of a monaural signal. The ring, used for the right channel in stereo systems, is used instead for the inverting input.

Advantages
Where space is a premium, TRS connectors offer a more compact alternative to XLR connectors, and so are common in small audio mixing desks.

Another advantage offered by TRS connectors used for balanced microphone inputs is that a standard unbalanced signal lead using a TS phone jack can simply be plugged into such an input. The inverting input on the ring contact gets correctly grounded when it makes contact with the plug body.

Disadvantages
When using non-switching phone connectors to make balanced audio connections, the socket grounds the plug tip and ring when inserting or disconnecting the plug, and the ground mates last. This causes bursts of hum, cracks and pops and may stress some outputs as they will be short circuited briefly, or longer if the plug is left half in.

This problem does not occur with XLR or when using gauge B which although it is of 0.25 in (6.35 mm) diameter has a smaller tip and a recessed ring so that the ground contact of the socket never touches the tip or ring of the plug. This type was designed for balanced audio use, being the original telephone switchboard connector and is still common in broadcast, telecommunications and many professional audio applications where it is vital that permanent circuits being monitored are not interrupted by the insertion or removal of connectors. This same tapered shape used in the gauge B plug can be seen also in aviation and military applications on various diameters of jack connector including the PJ-068 and Bantam plugs. The more common straight-sided profile used in domestic and commercial applications and discussed in most of this article is known as gauge A.

Alternatively, some switched audio jacks contain built-in isolated switches that only activate when the plug is fully inserted. This can be used to avoid the insertion issue, for instance by wiring the connectors through a double pole, double throw switch that activates only upon full insertion. Or for instance by having the switch control a circuit that gracefully ramps up the audio once the plug is fully-inserted and mutes the audio when not fully-inserted.

Unbalanced audio
Phone connectors with three conductors are also commonly used as unbalanced audio patch points (or insert points, or simply inserts), with the output on many mixers found on the tip and the input on the ring. This is often expressed as tip send, ring return. Older mixers and some outboard gear have unbalanced insert points with ring send, tip return.

In many implementations, the switch contact within the panel socket is used to close the circuit between send and return when the patch point has no plug inserted. Combining send and return functions via single $1/4$ in TRS connectors halves the space needed for insert jack fields which would otherwise require two jacks, one for send and one for return.

In some three-conductor TRS phone inserts, the concept is extended by using specially designed phone jacks that will accept a mono phone plug partly inserted to the first click and will then connect the tip to the signal path without breaking it. Standard TRS connectors may also be used in this way with varying success.

In some very compact equipment including modular synthesizers, 3.5 mm TS phone connectors are used for patch points.

title: Phone connector (audio)