363-206-295
Circuit Pack Descriptions
7-22 Issue 1 December 1997
Fault Detection Circuitry 7
The TG circuit pack has in-service and out-of-service built-in test capability. In-
service testing is continuous and errors are reported when they occur to the
SYSCTL via the intra-shelf control bus. An out-of-service test is performed
whenever the TG circuit pack is inserted or recovers from a transient failure.
The incoming DS1 references are monitored for:
■ LOS (128 consecutive zeros)
■ DS1 AIS
■ LOF
■ Excessive out-of-frame count
■ Greater than 10
-3
bit error ratio (BER).
Power Circuitry 7
The TG circuit pack receives two sources of −48 volts which are diode ORed,
fused, and filtered prior to conversion to a +5 volt source to power the rest of the
circuit pack. A failure of the fuse or converter causes the red FAULT LED to light.
TG Hardware Settings 7
The TG circuit pack option switches provide the following functions:
■ DS1 Reference Line Coding — Selects either alternate mark inversion
(AMI) or AMI with bipolar 8-zero substitution (B8ZS) line coding for both
DS1 input and DS1 output.
■ DS1 Reference Format — Selects either super frame (SF) or extended
super frame (ESF) for both DS1 input and DS1 output.
■ Timing Mode — Sets timing mode to free run, external DS1, or line
(formerly loop) timed.
■ DS1 output mode — Sets DS1 output (SF or ESF "all ones" signal) for
intra-shelf timing derived either from DS1 external input or from network
timing distribution derived from received line. Reference for DS1 timing
output is taken from the main OLIUs.
■ Sets equalizer switch for proper cable length when provisioned for SYNC
OUT mode. Equalizer settings will be automatically set to shortest cable
length when the DS1 output is provisioned for MULT mode.
To Next Page
Loading...
Need help?
General
