(CSU/DSU, or "..digital..") A
device that performs both the
channel service unit (CSU) and
data service unit (DSU) functions. The Channel Service Unit
(CSU) is used to terminate a
DS1 or
DS0 (56/64 kb/s)
digital circuit. It peforms
line conditioning, protection,
loop-back and timing functions. The Data Service Unit (DSU)
terminates the data circuit to the
Data Terminal Equipment
(DTE) and converts the customer's data stream into a bi-polar
format for transmission.