PictureTel Concorde 4500 Servicing Manual page 113

Table 4-5: Network or Communications Failure Checklist (Continued)
If you get
this
message... interface
(continued)
No Channel
Connection
Network Not
Ready
Type of
network It means...
Basic Troubleshooting Procedures
Do this...
If the NS LED is on for either
or both ports, this indicates
that the CSUs are not seeing
- 48 volts on the receive pair.
Continue with step 3.
If the LEDs are in normal idle
condition, call the network
provider. If the provider
indicates that the network is
operational, try replacing the
Communications Processor
board.
3. Disconnect the network cable
from the electronics module and
check pins 7 and 8 of RJ-48S with
respect to earth ground for - 48
volts.
If the check fails:
Check the same pins at the
wall jack. If this check is
successful, replace the
cable(s).
Perform the check at the
network providerÕs
demarcation point
(DEMARC). If the check is
successful, repair the wiring
between the wall jack and
the DEMARC.
If your network is still not
ready, call the network
provider.
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