How Headphone or Earphone works, working of TRS and TRRS

Introducation

In electronics, earphone jack is a family of connector typically used for analog signal, primarily for audio. It is cylindrical in shape, typically with two, three or four contacts. Three-contact versions are known as TRS connectors,

 Where

• T stands for "tip", R stands for "ring" and

• S stands for "sleeve".

• Similarly, two, three and four-contact versions are called TS, TRS and TRRS connectors respectively.

The phone connector was invented for use in telephone switchboards for switching in the 19th century and is still widely used. It is also termed an audio jack, phone jack, phone plug, and jack plug. Specific models are termed stereo plug, mini-stereo, mini jack, headphone jack, microphone jack,

        In its original configuration, the outside diameter of the "sleeve" conductor is ¹⁄₄ inch (exactly 6.35 mm). The "mini" connector has a diameter of 3.5 mm (approx. ¹⁄₈ inch) and the "sub-mini" connector has a diameter of 2.5 mm (approx. 3/32 inch).

 Modern Jack (Plug, connector)

Smart phone jack are available in two standard sizes. The 3.5 mm or miniature and 2.5 mm or sub-miniature sizes designed as two-conductor connectors for earpieces on transistor radios. All two sizes are now readily available in two-conductor (unbalanced mono) and three-conductor (balanced mono or unbalanced stereo) versions.

Four- and five-conductor versions of the 3.5 mm plug are used for certain applications. A four-conductor version is often used in compact camcorders and portable media players, and sometimes also in laptop computers and smartphones, providing stereo sound plus a video signal.

Proprietary interfaces using both four- and five-conductor versions exist, where the extra conductors are used to supply power for accessories. The four-conductor 3.5 mm plug is also used as a speaker-microphone connector on handheld amateur radio transceivers on some mobile phones. 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 many other items of audio equipment.

Mobile phones jack

Three- or four-conductor (TRS or TRRS) 2.5 mm and 3.5 mm sockets are common on cell phones, 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). Three-conductor 2.5 mm connectors are particularly common on older phones, while four-conductor 3.5 mm connectors are more common on newer smartphones. These are used both for handsfreeheadsets (esp. mono audio plus mic, also stereo audio plus mic, plus signaling for call handling) and for (stereo) headphones (stereo audio, no mic). Wireless (connectorless) headsets or headphones usually use the Bluetooth protocol.

There is no recognized standard for TRRS connectors or compatibility with three-ring TRS. The four rings of a TRRS connector are assigned to different purposes by different manufacturers. Any 3.5mm plug can be plugged mechanically into any socket, but many combinations are electrically incompatible. For example, plugging TRRS headphones into a TRS headset socket (or the reverse), plugging TRS headphones or headsets into a TRRS socket, or plugging TRRS headphones or headsets 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 microphone may or may not work, depending on wiring. Signaling compatibility depends both on wiring compatibility and the signals sent by the hands-free/headphones controller being correctly interpreted by the phone.

TRRS Standards

Standard	Tip	Ring 1	Ring 2	Sleeve	Phones using this Standard
OMTP	Left Audio	Right Audio	Microphone	Ground	old Nokia (and also Lumia starting from the 2nd gen), old Samsung (2012Chromebooks), old Sony Ericsson (2010 and 2011 Xperias), old Wiko (2012-)
CTIA /AHJ	Left Audio	Right Audio	Ground	Microphone	Apple, HTC, latest Nokia, latest Samsung, latest Sony (2012+), latest Wiko (2013+), Jolla, most Android phones

Notes:Nokia started to implement an universal audio connector, which enables the use of both American Headset Jack (AHJ) headsets and standard Nokia OMTP headsets.

The problem regarding to physical compatibility are:

·         If a two-conductor plug of the same size is connected to a three-conductor socket, the result is that the ring (right channel) of the socket is grounded. This property is deliberately used in several applications. However, grounding one channel may also be dangerous to the equipment if the result is to short circuit the output of the right channel amplifier. In any case, any signal from the right channel is naturally lost.

·         If a three-conductor plug is connected to a two-conductor socket, normally the result is to leave the ring of the plug unconnected (open circuit). In the days of vacuum tubes this was also potentially dangerous to equipment but most solid state devices tolerate this condition well. A 3-conductor socket could be wired as an unbalanced mono socket to ground the ring in this situation, but the more conventional wiring is to leave the ring unconnected, exactly simulating a mono socket.

Design

Examples of jack configurations, oriented so the plug 'enters' from the right. The most common circuit configurations are the simple mono and stereo jacks (A and B); however there are a great number of variants manufactured.

A.   A two-conductor TS phone connector. The connection to the sleeve is the rectangle towards the right, and the connection to the tip is the line with the notch. Wiring connections are illustrated as white circles.

B.   A three-conductor TRS phone connector. The upper connector is the tip, as it is farther away from the sleeve. The sleeve is shown connected directly to the chassis, a very common configuration. This is the typical configuration for a balanced connection. Some jacks have metal mounting connections (which would make this connection) and some have plastic, to isolate the sleeve from the chassis, and provide a separate sleeve connection point, as in A.

C.    This three-conductor jack has two isolated SPDT switches. They are activated by a plug going into the jack, which disconnects one throw and connects the other. The white arrowheads indicate a mechanical connection, while the black arrowheads indicate an electrical connection. This would be useful for a device that turns on when a plug is inserted, and off otherwise, with the power routed through the switches.
D. This three-conductor jack has two normally closed switches connected to the contacts themselves. This would be useful for a patch point, for instance, or for allowing another signal to feed the line until a plug is inserted. The switches open when a plug is inserted. A common use for this style of connector is a stereo headphone jack that shuts off the default output (speakers) when the connector is plugged in.

1.     Sleeve: usually ground

2.     Ring: Right-hand channel for stereo signals, negative polarity for balanced mono signals, power supply for power-using mono signal sources
3.     Tip: Left-hand channel for stereo signals, positive polarity for balanced mono signals, signal line for unbalanced mono signals

4.     Insulating rings

Uses

Some common uses of jack plugs and their matching sockets are:

·    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. 2.5 mm plugs are not as common, but are used on communication equipment such as cordless phones, mobile phones, and two-way radios.

·     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 video.

      ·    Hands-free sets and headsets often use 3.5 mm or 2.5 mm connectors. Phone connectors are used for mono audio out and an unbalanced microphone (with a shared ground). Four-conductor TRRS phone connectors are used to add an additional audio channel such as microphone input added to stereo output.
·     Microphone inputs on tape and cassette recorders.

·    Personal computers, sometimes using a sound card plugged into the computer. Stereo 3.5 mm jacks are used for:

·         Line in (stereo)

·         Line out (stereo)

·         Headphones/loudspeaker out (stereo)

·         Microphone input (mono, usually with 5 V power available on the ring. Note that traditional, incompatible, use of a stereo plug for a mono microphone is for balanced output)
·         LCD monitors with built-in speakers will need a cable with 3.5 mm male TRS plugs on each end to connect to the sound card.

·        Devices designed for surround output may use multiple jacks for paired channels (e.g. TRS for front left and right; TRRS for front center, rear center, and subwoofer; and TRS for surround left and right).

·        Electric guitars. Almost all electric guitars use a ¹⁄₄ in mono jack (socket) as their output connector. Some makes (such asShergold) use a stereo jack instead for stereo output, or a second stereo jack, in addition to a mono jack (as with Rickenbacker).

·      Instrument amplifiers for guitars, basses and similar amplified musical instruments. ¹⁄₄ in jacks are overwhelmingly the most common connectors. Electronic keyboards use jacks for a similar range of uses to guitars and amplifiers.

·       Some cameras (for example, Canon, Sigma, and Pentax DSLRs) use the 2.5 mm stereo jack for the connector for the remote shutter release (and focus activation); examples are Canon's RS-60E3 remote switch and Sigma's CR-21 wired remote control.

·  Some miniaturized electronic devices use 2.5 mm or 3.5 mm jack plugs as serial port connectors for data transfer and unit programming. This technique is particularly common on graphing calculators, such as the TI-83 series, and some types of amateurand two-way radio, though in some more modern equipment USB mini-B connectors are provided in addition to or instead of jack connectors. The second-generation iPod Shuffle from Apple has one TRRS jack which serves as headphone, USB, or power supply, depending on the connected plug.

·        Samsung YP-S MP3 player "pebble" uses USB-to-3.5mm TRRS jack adapter for charging as well as for data transfer.

·        On CCTV cameras and video encoders, mono audio in (originating from a microphone in or near the camera) and mono audio out (destined to a speaker in or near the camera) are provided on one three-conductor connector, where one signal is on the tip conductor and the other is on the ring conductor.

·        The Apple Lisa personal computer used a 3-conductor TRS phone connector for its keyboard.