Phone connector (audio)

Jack are internationally accepted electrical connector for AC or DC voltage in the low voltage range ( safety extra-low voltage, English Safety Extra Low Voltage, SELV). The design is standardized by the EIA RS- 453 and by the IEC 60603-11 below. Depending on the number of poles of the plug out of the top (tip ) and the shaft (sleeve ) has a different number of rings, resulting in the English name, for example, for the three-pin 6.3- mm (1 /4 " ) plug, colloquially audio jack as well.

Jack plugs, sockets and couplings include, for example, the transmission of audio signals and video signals or the connection to a power supply to power a small appliance. Very often jack used to connect headphones. Occasionally, they are used to transmit digital signals for control purposes.

The name is probably derived from jack in the sense of "leverage, which is to inhibit further movement of a machine part " and refers to the typical for this plug snapping to the contact springs for the useful signal. These contact springs, usually one or up to four, wherein the current designs of the bushings and connectors are also the only mechanical securing of the connector.

Advantages of linking pawl are ease of handling, space- saving design. Disadvantages are mainly the shorting plug-in process and the relatively poor contact quality. If the spring tension of the contact spring wears with time, not only the contact worse, but also the mechanical contact strength. The lack of mechanical lock can be a problem in the particular case when a undesirably solved connector may cause damage, such as the speaker connection of a tube guitar amplifier.

The contact load is at the 6.35 -mm sockets and couplings up to 3 A, the switching load 0.5 A at 50 V. The plugs are for more than 1,000 mating cycles and designed the sleeves for more than 10,000 cycles.

• 3.1 headphone port
• 3.2 line-level connection
• 3.3 Microphone Connection
• 3.4 Guitar Connection
• 3.5 insert
• 3.6 Data transmission
• 3.7 Power supply
• 3.8 speaker connection
• 3.9 Aviation

• 4.1 loose contacts
• 4.2 Short-circuit effects when plugging
• 4.3 Short-circuit effects by MONO plug, balanced connections
• 4.4 Likelihood of confusion
• 4.5 Overload

History

The existing today jack evolved from the plugs that were used in the hand placement attendants of the late 19th and early 20th century. Thus, the plug has one of the oldest and longest lines of evolution of the connector technology.

Designs

Jack be prepared with different shank diameters:

There are plug in versions with zero ( optical), two ( mono ), three ( stereo) and four (Stereo extra ) contacts.

From the United States in the German speaking less common names come from:

Mono plug ( two pin)

The mono plug leads at the top of the signal and on the rear part - the sleeve - the shield and return line ( " mass "). The transmission is therefore asymmetric.

Stereo plug ( three pins)

The stereo plug is the evolution of the mono plug. To accommodate the third contact for the second channel, a ring was separated from the sleeve.

The top is occupied by the signal for the left channel, the ring behind the tip with the signal for the right channel. The rear part of the sleeve, as is the single plug to the shield and return line. This type of signal transmission occurs also asymmetrical.

Balanced connection

In the professional audio technology usually symmetrical compounds are used in which the signal is separated from the shield and the ground potential via two equivalent lines - an in-phase (hot) and a phase -inverted (cold) - is transmitted. Since interference from stray usually affect both wires equally, the receiver can eliminate them by evaluating the difference of the two signals. The rear part of the sleeve, as is the single plug to the shield. If you put a mono plug into a socket wired symmetrically, one shorts the phase-reversed line to ground, which can cause damage depending on the circuit design. Often XLR connectors are used for symmetric encryption, because of space or cost reasons, but also often the same as jack for stereo connections.

For a phantom power for microphones are from the receiver ( amplifier, mixer) both signal lines connected to the same positive potential with respect to ground (usually 12 to 48 volts).

Stereo plug with additional function ( four pin)

If the AUX port is used as input for the microphone signal, the following standards shall be met:

• Variant A, OMTP ( Open Mobile Terminal Platform ) and
• Variant B, CITA ( Cellular Telecommunications Industry Association ).

The stereo plug with additional function is a variant of the stereo plug, wherein a further ring was separated from the shell and are thus a total of four contacts. Stereo plug with additional functions are mainly used in mobile phones and smartphones for connecting headsets. For the transmission of stereo audio and mono mic channel are two different variants of the pinout common. Both variants use the tip for transmitting the left audio channel and the first ring to the transmission of the right audio channel. In variant a microphone channel is transmitted to the second ring and ground is on the third ring or the bush. In variant B, also called inverted variant, the occupancy of the microphone channel and the mass is changed so that the mass is located on the second ring and the mic channel on the jack.

Both variants A and B allow the easy use of normal headphones with a three prong plug into a four-pin plug, since the pinout of the tip and first ring coincides with that of the three pin plug. The microphone channel is shorted by plugging directly to ground. A difference does the variant when a headset is connected to a three pin socket with dedicated contact spring for mass (but without contact for the stem ), as used for example in MP3 players or laptops. If a four-pin connector plugged into such a three-pin connector, the contact mass is located on the second ring. In variant A, it houses the microphone channel, so a headset with a pinout Alternative A in a three-pin socket can not be used. A headset with pin assignment according to variant B, however, can easily be used in three-pin sockets, since the mass here is on the second ring and is contacted by the socket correctly. The microphone channel in this case is without contact and without necessarily function.

The pin assignment according to variant A is used by older mobile phones of Nokia, Samsung and Sony Ericsson. The variant B is, however, Apple (iPhone, iPad, iPod and MacBook ), Xbox One stereo headset adapter, HTC, and used by newer Nokia, Samsung and Sony Phones. It is also used in some laptops from HP, Lenovo and Dell, as well as other devices. In some especially older phones the pinout may differ from the above-described variants. Standard accessories can then be used under certain circumstances only with adapters.

Special applications of the four-pole jack

Apart from the use for connecting headsets four-pole jack plug also for the transmission of multi-channel sound, audio and video signals and USB signals are used. On a mp3 player of the four -pole jack plug provides the ability to connect the MP3 player using the adapter via USB to the PC, which can account for an additional connector for USB.

Some camcorders or digital cameras, this plug is used to enable playback on a TV. The AUX port is assigned here to the composite signal. The pin assignment is not standardized in these cases and is determined by the manufacturer of the device.

Switching function

The socket or clutch can be equipped with an additional switch contacts which are actuated by the insertion process. Thus, often for devices with built-in speakers, this mute when a headphone plug is plugged into the appropriate port. Another example are devices that pause when the headphone plug is removed from the connector. In some guitar jacks and effects devices, there are switches that turn on the built-in impedance converter only when a cable is plugged.

Optical jack

There are also plug for the optical transmission of signals in the TOSLINK format. These are mainly used on notebook or PC sound cards. There are combined sockets that have both electrical contact phone plugs or via built-in optical transmitter or receiver.

Applications

For color coding of the plugs and sockets possibly see in characteristic color.

Since jack are generally not very mechanically robust, their field of application to more small electronic devices (including portable as smartphones) and consumer electronics ( including personal computers ) is limited. In professional audio ( sound ) or in the stage musical technique is more set on XLR connectors, only electric guitars are often still connected via 6.35 mm jack plug.

Headphone Connection

Three-pole stereo plug in the 3.5 mm version are available through headphones for portable devices since the 1980s, the conventional connector plug; miniature portable devices use 2.5 mm plug. In high-quality non- portable devices (eg hi-fi amplifier ) and in a professional environment, however, is the 6.35 - mm plug use.

Different manufacturers use a four -pole 3.5mm jack plug on portable devices, often to remote control the device by a small switch in the headphone cable. Usually, the additional contact may be shorted to ground easily, so that conventional headphones can be connected.

The company Apple uses the fourth contact with some laptops, there to output a composite video signal, so that a TV with a single plug can be connected. Again, the additional contact is short-circuited without damage to ground. Nokia provides this function on some smart phones (eg N95 ), the mobile phone can be connected to the TV. Even with some Sony camcorders the composite video signal is routed through the AUX contact.

Some manufacturers use in portable digital audio devices, a 3.5mm jack, the optical S / PDIF signal leads one to the top of the jack while a stereo signal to the conventional metal contacts. Thus, the headphone jack can be used as usual, but alternatively an entirely consisting of plastic plug ( " zero -pole " ) are inserted at the tip emerges a light pipe to the unit with an optical digital input, for example, at a HiFi to amplifier, connect. The contacts in the socket are used here only to keep the plug.

Line-level connection

The pin configuration is identical to the headphone jack, but the level is different and the external connection impedance higher than the headphones. Are usual 3.5mm stereo connector to portable devices and computers as well as 6.35 - mm connectors in mono and stereo in the semi-professional environment and for devices for musicians.

That stated above for unbalanced line outputs. However, the Line port on quality appliances is very often designed separately in 6.35 -mm technology and symmetrically for each channel.

The headphone jack can be temporary mode used as a line output, depending on the source, it is also possible that the headphone output is too low in level and the input can not disqualify sufficient. A headphone output is also adjustable in level and mostly in the frequency response. A line output has on the other hand - if at all - only a coarse level matching.

The commercial connectors for line-level (except for computers ) is RCA, older devices sometimes have DIN connectors, high-quality devices via balanced XLR connectors.

Microphone Connection

For stereo microphones the pinout is identical to the headphone jack, albeit with a much lower level and other impedance.

Mono microphones with mono plug lead, the signal at the tip and ground on the body of the plug, which occasionally takes place Tonaderspeisung over the top. Mono microphones with three-pin plug to use the tip for the signal, the ring for the power and ground on the body of the plug - if not balanced wiring ( as described above), optionally, used in combination with phantom power.

Many Sound Blaster compatible sound card (especially in laptops ) using a 3.5 mm stereo jack as a microphone input. Here, the signal at the tip and the mass is applied to the body of the plug. The annular contact is in a supply voltage (e.g. 1.5 V or 5 V ) from which, for example, a preamplifier can be powered for an electret. As a power supply for condenser microphones, this power is not suitable.

Microphones in the professional stage and studio range are connected usually does not have jack, but on XLR connectors. However, jack plugs are frequently used to connect microphones to portable devices (eg DAT recorder in the report area).

Guitar Connection

Electric guitars and electro-acoustic guitars usually have a 6.35 mm mono jack and can be connected via a cable with a mono plug into an amplifier input. The assignment is the same as the microphone port. There are also models that transmit a stereo signal via the stereo Share jack. In active pickup systems, a switching contact in the jack serve to power the integrated impedance converter on and off.

Insert

In order to grind for example a mixer effects processors into the signal cables are used with a stereo plug on one end and two mono plugs on the other end often. The signal is separated when plugging the stereo plug into the insert jack and ( usually of the "tip " of the stereo plug ) led to one of the mono plug. There, the input of the effects device is connected. About the other mono plug the output of the effects device is returned to the " ring " of the stereo plug into the mixer. The transmission is basically asymmetrical. This allows a simple mapping of the effects device to a channel of the mixer with only one mating. The assignment is not standardized. Usually, the tip, the signal is passed to the effect unit (which corresponds to the red plug ) and the ring (black connector of the Y cable ) back to the mixer, but also the opposite assignment is possible. Usually, the occupancy on the console or in the manual is documented.

Symmetrical compounds that are almost all consoles build by using the send and return path when these are balanced, in which case thus two cables must be used.

Data transmission

Some manufacturers of calculators use the standard jack to equip their devices with data transfer. Thus, individual variables, but also all the programs of calculator to calculator, but also of calculators are transmitted to the PC (eg the TI -83 series from Texas Instruments).

On the iPod shuffle ( 2nd generation) is used a four-pin plug for the transmission of a USB signal.

In music, electronics are also pure switching signals, for example, a foot switch, most often entrusted with 6.35 mm jack plugs.

Sensors for example, the pulse on exercise bikes are often equipped with plugs. Here's the lack of mechanical locking of advantage. If the cable is stretched, usually solved by the connector without causing damage to the connection.

Even for data backup on analog tape in older synthesizers came jack or jacks are used.

Some ECG machines older design had phone jacks, one of which came off the lines to the heart sensors.

Power supply

Jack 2.5 mm and 3.5 mm in diameter are uncommon for the power supply of small appliances for use. Since the contacts are open, it can already easily lead to a short circuit when inserting these connectors, the power supply used should therefore be designed to be short -circuit proof. In most cases, therefore, be used ( right) for the power supply barrel connector. However, neither the dimensions of the plug or the polarity at the contacts are standardized.

Speaker connection

Instrumental amplifier in the sound technology traditionally use jack connector for connecting internal and / or external speakers. TRS jacks and plugs are used especially when testing low to medium price range despite disadvantages:

• The contacts are not touch-proof. The SELV limit ( 25 volts AC ) is slightly exceeded.
• It high currents which pollute the jack plug system in border areas. With an output of 500 watts and a speaker impedance of 4 ohms, a current of more than 10 amperes is already flowing.
• On pressing the plug into the speaker amplifier is short-circuited, and can be destroyed in the on state.
• Inputs and outputs of devices and switch inputs (all typically 6.35 mm jack ) may be confused, thus high electrical power outputs can be connected in parallel inadmissible directed into sensitive inputs or.
• Tube amplifiers must not be operated without a speaker. If disengages the plug contact, the amplifier can be destroyed.

Aviation

In aviation, jack be used in different sizes:

• Civilian aircraft ( engine general aviation aircraft and commercial aircraft except for the XLR - connector -using Airbus models ): Headphones (headset ): 6.3mm jack plug two pin and rarely, three-pole, referred to as PJ 055
• Microphone (headset and hand-held microphone ): 5.23 mm jack ( 0.206 inch) two-pole, referred to as PJ 068

• Headphone, microphone (headset ): 7,13 mm jack plug ( 0.281 inch) with a total of four poles (peak plus two rings stem ), called the U174 / U or colloquially NATO Plug

Problems

Loose contacts

In particular, the smaller versions of the jack plug ( 3.5 mm and 2.5 mm ) are mechanically not very stable, so that bad connection may arise. In particular, the ground contact usually does not have a contact spring, contact problems occur here very frequently. The use of adapters or extensions exacerbated this problem. For this reason, it is almost exclusively used the 6.35 mm wide design with high-quality hi-fi equipment and professional use. Even here, however, with cheap models often lack the mass spring. This and for large diameters, however, the contact pressure is usually smaller again. Poor contact materials are common in all diameters. Higher-quality materials, lower mechanical tolerances ( and lower volumes ) condition the wide price range to professional applications. Important is in particular the ground contact (shaft), and there is often saved in the large plugs. The result is noise in the audio signal in mechanical movements and hum or worse stereo crosstalk.

Especially with many low -cost devices and cables, the contacts in the sockets and the plugs are running very inferior. Even factory- fresh contacts are bad, and they can also oxidize, and an unfavorable mechanical design due to loose contacts. Of these, the earth contact is very often affected, which can lead to a crosstalk of the two audio channels just with low-impedance loads ( headphones). At power -operated devices it bothers because with a high resistance between the device ground noise voltage between two points is formed. The ground connection is interrupted completely, the two transducers of the headphones between the signal outputs are connected in series in phase opposition. The monoglyceride content is wiped out and the stereo differences result in a typical bass - poor, poorly locatable, single-channel signal. For compositions, which then causes that the singing (or other central solo instruments ) remains only a Hall.

For many mobile devices, the jacks are soldered directly to the board and often inadequately bolted to the housing. When using relatively large leverage forces can occur, causing solder joints or in the worst case can even break parts of the board.

Short-circuit effects when plugging

Like the RCA plug connecting the first plug the signal lines and then the ground line. During the insertion of the tip ( left channel) first comes to the ground, then with the contact spring of the right channel, and finally to the contact spring of the left channel in contact. Analogous to the ring for the right channel only comes into contact with the mass, before it is applied to the contact spring for the right channel. This leads at the moment of insertion of the signal source almost inevitably produce noise when the cable leading to the entrance of an amplifier. Conversely, a jack cable will generate a short circuit when inserted at the signal load (eg speaker) at the amplifier output. ( For speakers see SPK - speakON, for line / microphone XLR see. )

Depending on the design and manufacture of quality bridge with some connections, the contact springs when you plug in even the insulation rings of the plug and thus lead to temporary short circuit of individual channels. Thus, the amplifier outputs can be shorted when you plug in a certain position, for example, in some headphone connections, as well as with some network devices with jack. While headphone amplifiers are usually short-circuit proof for small periods of time, all other connections should only be connected to devices disconnected to avoid overloads by such short-circuiting. Poor quality power supplies ( and cable) can itself be destroyed (or even destroy their environment).

Short-circuit effects by MONO plug, balanced connections

Mono and stereo jack connectors are electrically incompatible with: mono plug into stereo jacks connect the right channel to ground short, stereo plug to mono jacks are not connected (open) shorted for the right channel, or it is the right channel to ground. So this remains silent.

With professional studio equipment if the cable for unbalanced audio signals with mono jack in jacks for balanced connection (stereo jacks) are plugged, it creates a short circuit of the complementary ( inv) signal, which is on the right (ring ). The input and output and thus the connection is acting unbalanced.

An input then works just like a normal unbalanced input, so of course he loses the benefit of a symmetric data connection with differential signal.

A symmetrical output responds depending on the circuit but very different. High quality servo / floating outputs behave with a mono jack as easily as a single-ended output. The complementary ( inv) pole must necessarily be connected to ground for unbalanced operation here.

The frequent mass - balanced outputs, however, can show even increased distortion and a heavy burden of electronics in mono plugs next to the loss of the typical advantages of a symmetric connection. For those amplifiers, the short circuit of the complementary ( inv) pole is to be avoided. Here, it should therefore be used whenever possible, a stereo jack, but the ring will not be connected to ground, even if problems are not always immediately obvious.

If possible, the cable should be run two pole - pairs symmetrically with semi symmetrical compounds. The adaptation is then carried out exclusively on the unbalanced side. In unbalanced 6.35mm jack (MONO ) inputs the adaptation automatically and perfectly done, in many cases the unit that applies mostly for unbalanced MONO jack outputs. For pure 6.35 - mm - connections is so wired so as with symmetric connections. Otherwise, the cable and plug one side will be set up completely symmetrical, the adaptation takes place but then in the connector ( or an adapter ) on the unbalanced side to be connected (typically no then 6.35 mm jack plug or no line connection ). So some aspects of differential signal processing continue to be used yet. ( For cables to mass - balanced outputs the second wire may be omitted in the cable, so a cheaper coaxial cable can be used. Such outputs no advantages of a differential coupling can also be used with specially configured connections. ) Finished optimum cable are very rare for sale optimal adapter hardly.

For phone cables continues to note that stereo and balanced ( mono) cable from the outside can hardly be distinguished and are also usually not distinguished in the trade. For stereo cables, the two signal-carrying wires should be separately shielded, twisted- shielded balanced cables on the other hand. This also contributes to the uncertainty of wiring with plug.

Likelihood of confusion

For plugs that are used for power supply, a short circuit hazard, when the plug comes into contact with conductive objects. Thus, a conductive connection between the plug tip and sleeve arise, which can lead to the destruction of the power supply result. There is also confusion with headphones, microphone and line inputs. In such confusion in the worst case, all participating devices may be destroyed.

The documented here contact assignment for audio signals (speakers, headphones, etc. ) is used by all manufacturers. For power supplies, there is no agreement - depending on the manufacturer and device all combinations are possible: DC voltage to the negative pole to the sleeve and the positive pole at the top, DC voltage to the negative pole at the top and the positive pole to the sleeve or AC voltage to the tip and sleeve. Often given to the units or in the manual to determine which assignment is used, it is often the former.

High-quality special designs ( such as the products of the company Neutrik with mechanical interlock ) are more expensive than XLR connector, nevertheless allow them to compete only mechanically, as XLR connectors are much better usually screened.

Overload

If at 6.3 - mm plugs of max. 3 A assumed (see above), with speaker connections at 4 ohms maximum of 18 watts is allowed. This will almost always exceeded by musician electronics.

Color coding

For the 3.5 - mm connectors on Computer-Soundkarten/Mainboards a color coded inputs and outputs has been established according to the PC99 specification:

Often, alternatively switchable to the digital output.

The exact colors may vary in hue and saturation. The color coding is beyond and look at plugs, headphones, CD players, MP3 players and MiniDisc players.

Adapter

Many headphone manufacturers are placing their products with an adapter to operate the headphones on both devices with 3.5 mm and at 6.35 mm jack socket can. Are the headphones primarily intended for use on portable devices or computers, a 3.5 mm plug on the cable is used, on an adapter plug can be plugged or screwed to 6.35 mm. Conversely, use headphones, which are only occasionally run on portable devices, a 6.35 mm plug with an adapter plug or adapter cable to 3.5 mm, but due to the greater leverage of 6.35 - mm - plug the 3.5 mm jack can be damaged easily. For operation on a miniaturized equipment, there are adapter plugs and adapter cable to connect a 3.5 mm plug to a 2.5 mm jack.

If possible, the use of adapters should be avoided, as a result, the number of times in any case defective contacts is increased.