Connecting the Control Unit to the Network Interface

551 T1 CSU

The 551 T1 CSU performs many of the same functions as the ESF T1 CSU except for the following:

B8ZS is not supported.

Therefore, the 64-kbps clear channel is not supported.

Extended superframe (ESF) format is not supported.

if a network requires this format, the ESF T1 CSU must be used.

This CSU consists of the following components:

chassis with top and rear cover

Signal Monitor Unit (plug-in)

Office Repeater (plug-in)

Fault Location Filter (a factory-installed option)

FAULT LOCATION FILTER

AT&T 551 T1 Channel Service Unit

OFFICE REPEATER

SIGNAL MONITOR UNIT

Figure 4-8. 551 T1 CSU

Installing the Channel Service Unit

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AT&T Release 2.0 manual 551 T1 CSU