AT&T Release 2.0 manual Signal Monitor Unit Switch Settings

Connecting the Control Unit to the Network Interface

Signal Monitor Unit Switch Settings

There are four option switches in the signal monitor unit (see Figure 4-10).These switches govern the operation of the following options:

■ONES causes the unit to transmit an ALL ONES keep-alive signal to the central office when the customer signal drops below the minimum average ones-density.

■ESS (electronic switching system) causes the CSU to loop back its receive line to its transmit line (instead of generating ALL ONES) when the customer signal fails. The Ioopback framing pattern prevents false alarms at an ESS or a data acquisition control system (DACS).

■ZEROES selects either 16 or 50 consecutive zeroes to be the criteria for lighting the Zeroes LED.

■ACTIVE FAULT LOCATE causes the remote Ioopback path to preserve bipolar violations to allow single-ended fault locating when active fault filters are used. Table 4-21 shows the switch settings for the different options.

Figure 4-21. Signal Monitor Unit Switch Settings

O p t i o n

ONES

ESS

Switch Setting

#1 — closed

# 2 — open

#1 — open

# 2 — closed

ZEROES	#3 — closed for 16-zero limit
ACTIVE FAULT LOCATE	#4 — closed

Installing the Channel Service Unit 4-35