Filter
Top Products
12-12
Cisco Unified IP Phone 8961, 9951, and 9971 Administration Guide for Cisco Unified Communications Manager 8.5 (SIP)
OL-20861-01
Chapter 12 Troubleshooting and Maintenance
General Troubleshooting Tips
Loopback condition A loopback condition can occur when the following conditions are met:
• The SW Port Configuration option in the Network Configuration 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.
One-way audio 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.
Phone call cannot be established 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:
1. The Ethernet cable is attached.
2. The Cisco CallManager service is running on the Cisco Unified
Communications Manager server.
3. Both phones are registered to the same Cisco Unified Communications
Manager.
4. Audio server debug and capture logs are enabled for both phones. If needed,
enable Java debug.
Video transmitted by the camera is too
dark
The lighting conditions within the camera’s field of view affect the brightness of
the video.
• Adjust the View Area for your camera. Try moving the location of the
camera and check if the brightness improves.
• Adjust the camera brightness setting. See “Adjusting the Brightness
Setting” section on page 5-3 for instructions on how to adjust the brightness.
Poor video quality/grainy video When the resolution of the received video is grainy, the user may perceive that
the video quality is poor. However, this will not cause video distortion or
artifacts.
• Check the Cisco Unified Communications Manager bandwidth settings
under Region settings.
• Check the Receiver Resolution in video statistics. This may be an issue if
the Cisco Unified CM bandwidth setting limits the resolution to less than
CIF(352x288). Try increasing the bandwidth to at least 275 kbps.
Table 12-2 Cisco Unified IP Phone Troubleshooting (continued)
Summary Explanation