what is DSU/CSU ?

[magsam]

Is there anybody can tell me what is CSU/DSU ... cause it is not explained good in the ICND book ... thank u very much

 

[svermill]

This is a cut-and-paste from a disscussion last week or the week before:

I've always liked this passage in the Larscom Split-T manual:

"A Digital Service Unit (DSU) converts one or more subrate signals (i.e., signals transmitted at a subfrequency of the 1.544-Mbps T1 signal) to aT1 signal. Finally, a Channel Service Unit (CSU) is required to interface the customer’s T1 DTE or DSU to the public T1 network. The CSU provides various termination and interface functions as specified by AT&T Publication 62411 and FCC Rules, Part 68, including:

· Electrical interface.
· Surge and lightning protection.
· Signal regeneration and pulse density assurance.
· Keep-Alive and Yellow Signal.
· Loopback to the line controlled from the network."

Of course, you can poke around on the internet and try to find the Bellcore documents for blood-and-guts details, but the above is a nice overview.

 

[maktop]

DSU/CSU is an acronym 4 data service unit and chanell service unit.they are both data communication equipment that connect to the network portion of user-network data communication.data terminal equipment (DTE) such as router is connected to DSU/CSU while DSU/CSU is connected right to the demarc.they provide clocking and other functions to DTE.in the absense of DSU/CSU where u have end to end connection, u have to configure the serial inter. of the DTE to provide clocking.u can type show conrollers serial0 at the priviledge mode to determine if have DTE or DCE

 

[jtb]

essentially, as the above references state, it's a specialized modem.

wan circuit --- csu/dsu --- router serial interface JTB
Solutions Architect
MCSE-NT4, MCP+I, MCP-W2K, CCNA, CCDA,
CTE, MCIWD, i-Net+, Network+
(MCSA, MCSE-W2K, MCIWA, SCSA, SCNA in progress)