Objective 2.2: Connectors
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Objective 2.2: Identify common connector types
RJ-11 (Registered Jack 11)
RJ-11 is a physical interface often used for terminating telephone wires. It is probably the most familiar of the registered jacks, being used for single line Plain Old Telephone Service (POTS) telephone jacks in most homes across the world.
RJ-14 is similar, but for two lines, and RJ-25 is for three lines. The telephone line cord and its plug are more often a true RJ-11 with only two conductors.
| position | RJ25 pin | RJ14 pin | RJ11 pin | Pair | T/R | ± | Cat 5e/6 colors | Colors | Old colors |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 1 | 3 | T | + |  white/green |
white/green |
 orange | ||
| 2 | 2 | 1 | 2 | T | + |  white/orange |
white/orange |
 black | |
| 3 | 3 | 2 | 1 | 1 | R | – |  blue |
 blue/white |
 red |
| 4 | 4 | 3 | 2 | 1 | T | + |  white/blue |
white/blue |
 green |
| 5 | 5 | 4 | 2 | R | – | orange |
 orange/white |
 yellow | |
| 6 | 6 | 3 | R | – | green |
 green/white |
blue |
RJ-45 (Registered Jack 45)
The 8 Position 8 Contact (8P8C) (often incorrectly called RJ-45) plugs and sockets are most regularly used as an Ethernet connector. 8P8C connectors are typically used to terminate twisted pair cable.
BNC (Bayonet Neill-Concelman)
The BNC (Bayonet Neill-Concelman) connector is a very common type of connector used for terminating coaxial cable. The BNC connector is used for RF signal connections, for analog and digital video signals, amateur radio antenna connections, aviation electronics (avionics) and many other types of electronic test equipment. It is an alternative to the RCA connector when used for composite video on commercial video devices, although many consumer electronics devices with RCA jacks can be used with BNC-only commercial video equipment via a simple adapter.
SC (Subscriber Connector or Standard Connector)
A fiber-optic connector with a push-pull mechanism to allow locking in place while still being simple to insert and remove.
ST (Straight Tip)
A fiber-optic connector with a socket that is locked in place with a bayonet lock. ST was the first de-facto standard for fiber-optic cabling, and has since been made an official standard.
LC (Local Connector or Lucent Connector)
Developed by Lucent. It looks like a smaller version of the SC connector. It is used in Telco environments.
RS-232 (Recommended Standard 232)
RS-232 (Recommended Standard 232) is a standard for serial binary data signals connecting between DTE (Data Terminal Equipment) and DCE (Data Circuit-terminating Equipment). It is commonly used in computer serial ports.