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Cisco Unified IP Conference Station 7937G Administration Guide for Cisco Unified Communications Manager 6.0
OL-11560-01 Rev. B0
Chapter 9 Troubleshooting and Maintenance
General Troubleshooting Tips
Loopback condition A loopback condition can occur when the following conditions
are met:
• The conference station receives power from an external
power supply
• The conference station is powered down (the power supply
is disconnected)
In this case, the switch port on the conference station can
become disabled and the following message will appear in the
switch console log:
HALF_DUX_COLLISION_EXCEED_THRESHOLD
To resolve this problem, re-enable the port from the switch.
Moving a network connection from
the conference station to a
workstation
If you are powering your conference station through the
network connection, you must be careful if you decide to
unplug the conference station’s network connection and plug
the cable into a desktop computer.
Caution The computer’s network card cannot receive power
through the network connection; if power comes
through the connection, the network card can be
destroyed. To protect a network card, wait 10
seconds or longer after unplugging the cable from
the conference station before plugging it into a
computer. This delay gives the switch enough time to
recognize that there is no longer a conference station
on the line and to stop providing power to the cable.
No dial tone Check that all connections are secure and in place. Make sure
all connections are correct.
No LCD screen display Check to make sure that the conference station has power.
Make sure that the power supply unit is plugged in.
One-way audio When at least one person in a call does not receive audio, IP
connectivity between conference stations is not established.
Check the configurations in routers and switches to ensure that
IP connectivity is properly configures.
Table 9-1 Cisco Unified IP Conference Station 7937G Troubleshooting (continued)
Summary Explanation
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