XLR connector
The generic term "XLR" began as a trademark of Cannon Electric, with the letters standing for X model connector with an added "l"atch feature, and "r"esilient neoprene rubber surrounding the female contacts.
There was also the XLP series of connectors with hard plastic insulation, but the XLR model name is commonly used for all of the variants.
[2][3][4] Originally, the ITT Cannon company manufactured XLR connectors in two locations: Kanagawa, Japan, and Melbourne, Australia.
XLR connectors are available in male and female versions in both cable and chassis mounting designs, a total of four styles.
[i] XLR are unusual as, at least in audio applications, all four combinations of male and female, plugs and sockets are equally common.
There is a loose convention for audio work that signals are generated by equipment with male pins and transmitted to those with female receptacles.
[citation needed] Three-pin XLR connectors are by far the most common style, and are an industry standard for balanced audio signals.
[7] Three-pin XLR connectors are used to interconnect powered speakers with line-level signals used for PA system applications.
[citation needed] An obsolete use for three-pin XLR connectors was for MIDI data on some Octave-Plateau synthesizers including the Voyetra-8.
The three-pin XLR connector is commonly used for DMX512, on lighting and related control equipment,[8] particularly at the budget / DJ end of the market.
[9] Use of the three-pin XLR in this context firstly presents a risk of damage to the lighting equipment should an audio cable carrying 48-volt phantom power be accidentally connected.
[citation needed] Another common use is for DC power connections for professional film and video cameras and related equipment.
[citation needed] Additionally, five-pin XLR is commonly used for DC power in audio equipment.
[citation needed] XLR 5 is used in aviation headsets, where it can supply power for active noise cancellation.
Six-pin XLR connectors are used for dual channel intercom systems[14] and stage lighting control applications.
[citation needed] Seven-pin XLR connectors are used to connect some valve (tube) condenser microphones to their power supplies (carrying signal, polarisation voltage, heater and HT).
A two-pin variant was used as the DC power input socket on Yamaha's 1970s CP-series 'Electric Grand' pianos (CP-60, CP-70 and CP-80).
AES standards mentioned above recommend that shells of cable-mounted connectors should never be connected to pin 1 or the shield, because inadvertent contact of the shell with another grounded surface while in use can create unwanted current paths for fault current, potentially causing hum and other noise.
The argument centers on the radio frequency shielding provided by the shell of the connector, which may be reduced if it is left floating.
[24] The five-pin XLR is the standard connector for DMX512, the most common protocol for controlling professional lighting and related equipment.
[9] Five-pin XLR is also a common power connector in modular professional audio systems, such as the Automated Processes, Inc.'s (API) Lunchbox format.
Three-pin XLR connectors were once used extensively on loudspeaker cables, because when first introduced they represented a new standard of ruggedness, and economical alternatives were not readily available.
Phantom power is usually supplied at a nominal 48 volts DC, although lower voltages are permissible and modern microphones will often operate over a wide range.
The XLD connector is proposed by the Audio Engineering Society AES42 digital microphone interface standard.
The Mini XLR Connector, also known as the "TQG" [31] or "TA3"/"TA4"[32] connector (number depending on number of poles), is used on compact items such as UHF wireless microphone beltpacks, some studio and field recording headphones, as well as Audio Technica condenser microphones, but is not in general use on major items such as mixing desks.
