CSU/DSU
 

CHANNEL SERVICE UNIT/DATA SERVICE UNIT

A CSU/DSU (Channel Service Unit/Data Service Unit) is a hardware device about the size of an external modem that converts digital data frames from the communications technology used on a local area network (LAN) into frames appropriate to a wide-area network (WAN) and vice versa. For example, if you have a Web business from your own home and have leased a digital line (perhaps a T-1 or fractional T-1 line) to a phone company or a gateway at an Internet service provider, you have a CSU/DSU at your end and the phone company or gateway host has a CSU/DSU at its end.

The Channel Service Unit (CSU) receives and transmits signals from and to the WAN line and provides a barrier for electrical interference from either side of the unit. The CSU can also echo loop-back signals from the phone company for testing purposes. The Data Service Unit (DSU) manages line control, and converts input and output between RS-232C, RS-449, or V.35 frames from the LAN and the time-division multiplexed (TDM) DSX frames on the T-1 line. The DSU manages timing errors and signal regeneration. The DSU provides a modem-like interface between the computer as Data Terminal Equipment (DTE) and the CSU.

CSU/DSU Products

	Paradyne Acculink 3150 CSU Refurbished Price:US$800.00		Paradyne Acculink 3160 CSU Refurbished Price:US$875.00
	Paradyne Acculink 3164 CSU/DSU Refurbished Price:US$875.00		Definity Integrated Channel Service Unit (ICSU 120A3) Price US$900.00