Cisco 6941 - Unified IP Phone Slimline VoIP Administration Manual page 151

Chapter
Table 9-2 Cisco Unified IP Phone Troubleshooting (continued)
Summary
Sound sample mismatch between the
phone and another device.
Gaps in voice calls.
Loopback condition.
One-way audio.
Phone call cannot be established
Cisco Unified IP Phone 6921, 6941, 6945, and 6961 Administration Guide for Cisco Unified Communications Manager 8.5 (SCCP and SIP)
OL-23769-01
Explanation
The RxSize and the TxSize statistics show the size of the voice packets that are
being used in a conversation between this Cisco Unified IP phone and the other
device. The values of these statistics should match.
See the "Call Statistics Screen" section on page 7-8
displaying these statistics.
Check the AvgJtr and the MaxJtr statistics. A large variance between these
statistics might indicate a problem with jitter on the network or periodic high
rates of network activity.
See the "Call Statistics Screen" section on page 7-8
displaying these statistics.
A loopback condition can occur when the following conditions are met:
• The SW Port Configuration option in the Network Setup menu on the
phone is set to 10 Half
(10-BaseT / half duplex)
The phone receives power from an external power supply
•
The phone is powered down (the power supply is disconnected)
•
In this case, the switch port on the phone 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.
When at least one person in a call does not receive audio, IP connectivity
between phones is not established. Check the configurations in routers and
switches to ensure that IP connectivity is properly configured.
The phone does not have a DHCP IP address, is unable to register to Cisco
Unified Communications Manager, and shows a Configuring IP or Registering
message.
Verify the following:
The Ethernet cable is attached.
1.
The Cisco CallManager service is running on the Cisco Unified
2.
Communications Manager server.
Both phones are registered to the same Cisco Unified Communications
3.
Manager.
Audio server debug and capture logs are enabled for both phones. If
4.
needed, enable Java debug.
General Troubleshooting Tips
for information about
for information about
9-11