AT&T MERLIN LEGEND Installation & Maintenance Manual page 138

Installation
CAUTION:
Connecting an ESF T1 CSU provisioned for Iocal power—
wet loop to digital microwave, digits/multiplexers, or fiber
optics can damage the equipment. Connecting an ESF T1
CSU provisioned for local power — wet loop with span-line
power present can damage the CSU. Therefore, the local
power — wet loop option can be used only in private
networks with user-owned facilities.
Local power is required for total unit operation no matter
which method of power is selected.
Note: Select local power—dry loop in almost all cases. If span-
Iine power is provided and the telephone company agrees, you
can option the CSU for SP. However, most telephone companies
do not provide span-line power for new installations.
Set the Artificial Transmit Line Option
Depending on the distance from the CSU to the first line
repeater, set the Line Build-Out (LBO) switch to the proper
option (see Table 3-12). The LBO switch is accessed through the
top panel of the CSU.
Notes:
The required setting for the LBO switch is usually specified by
the telephone company.
The receive path contains a fixed 7.5 dB artificial line and an
automatic line build-out (ALBO) circuit, which automatically
compensate for signal levels in the range of 0 to -27.7 dB.
3-30 Channel Service Unit