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Old-style male tip-sleeve ("pin"
or "jack") connectors. The leftmost plug has three conductors; the
others have two.
At the top is a three-conductor jack from the
same era.
Modern profile 2-conductor male 1/4? TRS connectors.
In the original application in manual telephone exchanges, many different configurations
of 1/4? jack plug 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 many other items of audio equipment.
When a three-conductor version of the 1/4? jack was introduced for use with
stereo headphones, it was given a sharper tip profile in order to make it possible
to manufacture jacks (sockets) that would
accept only stereo plugs, to avoid short-circuiting the right channel amplifier.
This attempt has long been abandoned, and now the normal convention is that
all plugs fit all sockets of the same size, regardless
of whether they are balanced mono, unbalanced mono or stereo. Most 1/4? plugs,
mono or stereo, now have the profile of the original stereo plug, although a
few rounded mono plugs are also still
produced. The profiles of stereo miniature and subminiature plugs have always
been identical to the mono plugs of the same size.
The results of this 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, see "tip ring sleeve", below.
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 valves ("tubes" in the U.S.) 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.
Some common uses of jack plugs and their matching sockets are:
* Headphone and earphone jacks on a wide range of equipment. 1/4?
plugs are common on home and professional component equipment, while 1/8? plugs
are nearly universal for portable audio
equipment. 3/32? 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 1/8? connectors for composite video and audio output.
Typically, a TRS connection is used for
mono audio plus video, and a TRRS connection for stereo
audio plus video. Cables designed for this use are often terminated with RCA
connectors on the other end.
* Microphone inputs on tape and cassette recorders, sometimes with
remote control switching on the ring.
* Patching points (insert points) on a wide range of equipment.
* Personal computers, sometimes using a sound card plugged into
the computer. Stereo 1/8? jacks are used for:
* Line in (stereo)
* Line out (stereo)
* Headphones/loudspeaker out (stereo)
* Microphone input (mono, usually with 5
volt power available on the ring. Note that traditional, incompatible, use of
a stereo plug for a mono microphone is for balanced output)
* Laptop computers generally have one line
level jack for headphones and one mono jack for a microphone at microphone level.
You can use an attenuating cable to convert line level or use a
signal from an XLR connector,
but it is not designed to record from a stereo device such as a radio or music
player.
* LCD monitors with built-in speakers will
require a 1/8? male-male cable from the sound card.
Note: Higher end sound cards sometimes sport a breakout
panel which supports 1/4? plug devices as well.
* Devices designed for surround output may
use multiple jacks for paired channels (ex. TRS for front left and right; TRRS
for front center, rear center, and subwoofer; and TRS for surround left
and right). Circuitry on the
sound device may be used to switch between traditional Line In/Line Out/Mic
functions and surround output.
* Electric guitars. Almost all electric guitars use a 1/4? mono
jack (socket) as their output connector. Some makes (such as Shergold) 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? jacks are overwhelmingly the most common connectors
for:
* Inputs. A shielded cable with a mono 1/4?
jack plug on each end is commonly called a guitar cord or a patching cord, the
first name reflecting this usage, the second the history of the jack
plug's development for use in
manual telephone exchanges.
* Loudspeaker outputs, especially on low-end
equipment. Speakon connectors are generally considered superior and so are usually
preferred on higher-end equipment, although it is not
uncommon to find both provided
for compatibility. Heavy-duty 1/4? loudspeaker jacks are rated at 15A maximum
which limits them to applications involving less than 1,800 watts. 1/4?
loudspeaker jacks commonly aren't
rigged to lock the plug in place and will short out the amplifier's output circuitry
if connected or disconnected when the amplifier is live.
* Line outputs.
* Foot switches and effects pedals. Stereo
plugs are used for double switches (for example by Fender). There is little
compatibility between makers.
* Effects loops, which are normally wired
as patch points.
* Electronic keyboards use jacks for a similar range of uses to
guitars and amplifiers, and in addition
* Sustain pedals.
* Expression pedals.
* Electronic drums use jacks to connect sensor pads to the synthesizer
module or MIDI encoder. In this usage, a change in voltage on the wire indicates
a drum stroke.
* Some compact and/or economy model audio mixing desks use stereo
jacks for balanced microphone inputs.
* The majority of professional audio equipment uses mono jacks as
the standard unbalanced input or output connector, often providing a 1/4? unbalanced
line connector alongside (or in a few cases in
the middle of!) and as an alternative to an XLR balanced
line connector.
* Modular synthesizers commonly use monophonic cables for creating
patches.
* ¼ in connectors are widely used to connect external processing
devices to mixing consoles' insert points (see Insert (effects processing)).
TRS or TS connectors might be used in pairs as separate
Send and Return jacks or a single TRS jack might be
employed for both Send and Return in which case the signals are unbalanced.
The single unbalanced combination Send/Return TRS insert jack
saves both panel space and component complexity. Note
that mixing console insert points can also be XLR, RCA or Bantam TT (tiny telephone)
jacks, depending on the make and model.
* Some small electronic devices such as audio cassette players,
especially in the cheaper price brackets, use a two-conductor 1/8? or 3/32?
jack as a DC power connector.
* Some photographic studio strobe lights have 1/4? or 1/8? jacks
for the flash synchronization input. A camera's electrical flash output (PC
socket or hot shoe adapter) is cabled to the strobe light's
sync input jacks. Some examples: Calumet Travelite,
and Speedotron use a 1/4? mono jack as the sync input; White Lightning uses
1/4? stereo jacks; Pocket Wizard (radio trigger) and Alien Bees
use 1/8? mono jacks.
* Some cameras (for example, Canon, Sigma, and Pentax DSLRs) use
the 3/32? 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 3/32? or 1/8? 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 amateur
and 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 a
single TRS jack which serves as headphone, USB, or power supply, depending on
the connected plug.
* 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 a
single three-conductor connector, where one signal is
on the tip conductor and the other is on the ring conductor.[8]
* The Atari 2600 (Video Computer System), the first widely popular
home video game console with interchangeable software programs, used a 1/8?
TS (two conductor) jack for 9V(?) DC power.