RJ48

RJ48 is a registered jack. It is used for T1 and ISDN termination and local area data channels/subrate digital services. It uses the8 position modular connector.

RJ48C is commonly used for T1 lines and uses pins 1, 2, 4 and 5.

RJ48X is a variation of RJ48C that contains shorting blocks in the jack so that a loopback is created for troubleshooting when unplugged by connecting pins 1 and 4, and 2 and 5.

RJ48S is typically used for local area data channels/subrate digital services, and carries one or two lines. It uses a keyed variety of the 8P8C modular connector.

RJ48 connectors are fastened to STP (Shielded Twisted Pair) cables, not the standard UTP (Unshielded Twisted Pair) CAT-(1-5).

Naming confusion

People sometimes refer to the 10P10C modular connector as "RJ48." The origin of this misnomer is unknown; none of the RJ48 registered jacks use a 10P10C connector. However, it may be an outgrowth of the common misperception of the "RJ" USOCs as names of physical connectors. If one knew of the names RJ45 and RJ48 and knew of the 8P8C and 10P10C modular connectors, and believed (as explained in the RJ45 article) that RJ45 is the name of the 8P8C, one might conclude that RJ48 is the name of the larger 10P10C.

External links

* [http://www.arcelect.com/RJ48C_and_RJ48S_8_position_jack_.htm RJ48C and RJ48S RJ48X]
* [http://www.bytepile.com/T1_T3_cable_RJ48.php T1 & T3 RJ48 Cables]