Channel service unit/data service unit
<communications, hardware> (CSU/DSU, or "..digital..") A device that performs both the channel service unit
(CSU) and data service unit
The Channel Service Unit (CSU) is used to terminate a DS1
(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.