Gender of connectors and fasteners
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In electrical and mechanical trades and manufacturing, each of a pair of mating connectors or fasteners is conventionally assigned the designation male or female. The assignment is by direct analogy with genitalia and sexual intercourse; the part bearing one or more protrusions, or which fits inside the other, being designated male and the part containing the corresponding indentations or fitting outside the other being female.
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[edit] Definitions
The terms "slot", "socket", "receptacle" and "outlet" are often used for "female" connectors, and "plug", "prong" or "pin" for "male" connectors. In many cases these terms are more common than male and female, especially in documentation intended for the non-specialist. It also causes a fair amount of confusion when those names are shortened in labels. For example, the male component of an HD15 connector can be named either HD15M or HD15P (HD15F or HD15S for female versions), both of which mean the same thing but could be confused for different items when there is no accompanying picture. Further confusion can be caused by the term Jack, which is used for both female and male connectors.
IEEE STD 100 and ANSI Y32.16 define "plug" and "jack" by location or motion, rather than gender. A connector in a fixed location is a jack, and a moveable connector is a plug. The distinction is relative, so a portable radio is considered stationary compared to the cable from the headphones; the radio has a jack, and the headphone cable has a plug. It is common practice to use female connectors for jacks, so the informal gender-based usage often agrees with the functional description of the technical standards. This is not always the case, so it is best to use "male" and "female" for gender, and "plug" and "jack" for function.
[edit] Safety
In electrical connections where voltage is sufficient to cause injury, the part connected to the power source is invariably female, to prevent inadvertent contact. A plug is on the cord of (or on) the device drawing the power.
In low-voltage use, such as for data communications, this is less important, and male or female connectors are used based on other engineering factors such as convenience of use or ease of manufacturing. For example, the common "patch cables" used for Ethernet hookups (and the similar cords used for telephones) typically have plugs on both ends, to connect to jacks on equipment or mounted in walls. A device called a gender changer may be used to join two connectors of the same gender, for example, to extend one video cable with another.
The gender of a connector is determined by the structure of its primary functional components — i.e., the conductors of an electrical connector, or the load-bearing parts of a fastener — and not by secondary features such as covers, shields or handles that may be installed for environmental protection, safe operation, etc.
[edit] Genderless connectors
Certain connector designs (such as the SAE connector, and jackhammer air hose connectors) involve paired identical parts each containing both protrusions and indentations. The term hermaphrodite (or hermaphroditic) is used for such devices, along with genderless, combination (and combo), two-in-one, two-way, and others.
Some connectors have both male and female connectors on opposite sides, designed to be placed between a male and female to intercept a signal or to take power. These may also be referred to as hermaphrodite connectors, or alternately vampire or parasite plugs. These were once used for PC accessories, placed between the output of an AT power supply and a monitor so these accessories would be disconnected from power when the computer was switched off, but are now impractical with the dominance of ATX supplies which lack a mains output socket.
[edit] Examples
- A power cord on a appliance terminates in a (male) plug; it connects to a (female) socket in a wall or on an extension cord.
- Co-axial cables used for video or other high-frequency signals are normally terminated, at both ends, in a connector comprising an inner pin and an outer fixed or rotating shell; these are conventionally reckoned as male.
- A nut is female and a bolt is male.
- Connectors for air brake hoses on heavy trucks and railroad equipment use genderless "gladhand" connectors. In railroad use, this makes the orientation of rolling stock irrelevant, and is used with the standard North American railroad coupler that connects cars together, also genderless.
- Piping and plumbing fittings
