56K CSU/DSU   RJ-48S Connector

To connect a Bridge or Router to a 56K, CSU/DSU Network, T3, T1 or Fractional T1 line, use a cable with an RJ-48S jack connector.The RJ-48 connector may look very similar to an RJ-45 connector found on a typical CAT-5 cable, but don’t be fooled, they are very different in many ways.A RJ-48 connecter is fastened on to a STP (Shielded Twisted Pair) cable, not the standard UTP (Unshielded Twisted Pair) CAT-(1-5) cable.A RJ-48 also uses a different pin out arrangement, voltage level, and line capacitance then a RJ-45.See below for details on the RJ-48C, and RJ-48X connectors.

Pin Assignments for a RJ-48S Jack Connector.

 

Pin Assignments of a cable with both ends terminated with RJ-48S connectors.

 

RJ-48S for DDS Telco on RJ-45

UNIVERSAL SERVICE ORDER CODE (USOC): RJ-48S

Mechanical Arrangement: Miniature 8-position keyed jack. Typical Usage: Local area Data Channels or Sub Rate Digital Services.  Electrical Network Connection: One or two line T&R or T&R T1 R1.

RJ-48C

UNIVERSAL SERVICE ORDER CODE (USOC): RJ-48C

Mechanical Arrangement: Miniature 8-position jack. Typical Usage: 1.544 Mbps digital services.  Electrical Network Connection: Single Line T&R, T1 R1, conductors 7 and 8 provide cable shield integrity.Conductors 3 and 6 are reserved for future use.

RJ-48X

UNIVERSAL SERVICE ORDER CODE (USOC): RJ-48C

Understanding the USOC and RJ-xx Codes

Then following will help break down what those USOC and RJ-xx codes really mean. The Universal Service Ordering Code (USOC) system was developed by the Bell System and introduced by AT&T in the 1970s to connect customer premises equipment to the public network. These codes, adopted in part by the FCC, Part 68, Subpart F, Section 68.502, are a series of Registered Jack (RJ) wiring configurations for telephone jacks that remain in use today.

Registered Jack numbers end with a letter indicating the wiring or mounting method being used.

• "C" - Identifies a surface or flush mounted jack.
• "W" - Identifies a wall mounted jack.

If you (the telphone subscriber) want to have a standard jack other than the RJ-xxW or RJ-xxC installation, you should specify the appropriate USOC when requesting the installation.

• "S" - Identifies a Single-line jack.
• "M" - Indentifies a Multi-line jack.
• "X" - Identifies a Complex Multi-line or Series Type jack.

You may also see these terms associated with the USOC code system.

• "T/R" - Denotes connections to the Tip and Ring wires of a Telephone Communictions Line, Trunk Channel, or Facility.
• "A/A1" - Signifies connections to the Hold Functions of key telephone systems. The "A" lead corresponds to a particular line shorted to the "A!" lead when that line is Off-hook in order for that line's "Hold" function to operate correctly.
• "Bridged" - Signifies a Parallel Connection.
• "Data" - Data configurations use jacks that incorporate components to Limit Signal Power Levels of Data Equipment.