Specifications

120A channel service unit
Issue 6 February 2007 211
Circuit packs, channel service units,
and power supplies
120A channel service unit
The 120A channel service unit (CSU), when combined with a DS-1 circuit pack, provides an
integrated CSU that:
● Converts digital frames for communications between a local area network and wide area
network
● Provides a barrier for electrical interference from either side of the unit
● Echoes loopback signals for testing the network
The 120A CSU performs similar functions to an external CSU but with the following advantages:
● Increased reliability
● Uses less equipment and space
● Powered by the system
● Easier to install and operate
The 120A CSU connects to a DS1 circuit pack via the I/O connector panel on the back of the
cabinet. A modular cable plugs into the CSU module at one end and into a 700A loopback jack,
smart jack, or other service-provider interface on the other end.