Jack

In electronics and electrical assemblies, the term jack commonly refers to a surface-mounted connector, often with the female electrical contact or socket, and is the "more fixed" connector of a connector pair. The related term "jack plug" commonly refers to a "less fixed" connector of a connector pair, often with the male electrical contact or pin, and is generally shortened to simply "plug."

Some connector styles^[1] may contain male (pin), female (socket) or both connection types. Therefore, the use of gender to describe a connector "jack" or "plug" is misleading at best and inappropriate. A jack is properly described as a connector that is designed to be mounted (fixed) on the surface of a bulkhead or enclosure; "The stationary (more fixed) connector of a mating pair shall be designated J or X"^[2] where J means jack^[3]. Its counterpart, the "plug," is designed to attach to a wire, cable or removable electrical assembly; "The movable (less fixed) connector of a mating pair shall be designated P"^[4] where P means plug. This convention is currently defined in ASME Y14.44-2008 which is the current actively maintained follow on to the withdrawn IEEE 200-1975; IEEE 200-1975 was derived from the long withdrawn MIL-STD-16 which dates back at least to the 1950s which highlights the heritage of this connector naming convention.

The term jack occurs in several related terms:

• The "RJ" prefix which stands for "registered jack" in RJ11, RJ45 and similar connectors, and includes the modular jacks used in modern telephone systems and computer network interfaces (i.e., "Ethernet jack").

• The telephone jack of old-style manual telephone switchboards, which is the socket fitting the original 1/4" telephone plug.

• The 1/4" phone jack common to many electronic applications, either in a 2-conductor tip-sleeve (TS) or 3-conductor tip-ring-sleeve (TRS) configuration.

• The RCA jack, also known as a "phono jack", common to consumer electronics.

• The EIAJ jack designed for consumer appliances requiring less than an 18.0 volt power supply.

When preceded by a diameter, the term refers to the jack that matches the corresponding diameter of plug. For example:

• 6.35mm or 1/4" jack
• 3.5mm miniature jack
• 2.5mm subminiature jack

A headphone (or earphone) jack is commonly one of the three standard sizes of 3-conductor TRS jacks, but the term could refer to any socket used for this purpose.

References

Foreman, Chris, "Sound System Design", Handbook for Sound Engineers, Third Edition, Glen M. Ballou, Ed., Elsevier Inc., 2002, pp. 1171-2.

This article needs additional citations for verification. Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (July 2009)

See also

• TRS connector
• Home cinema
• Line level
• Sound card
• Keystone module