Cisco Systems 8961 manual Halfduxcollisionexceedthreshold, 12-12

Chapter 12 Troubleshooting and Maintenance

General Troubleshooting Tips

Table 12-2	Cisco Unified IP Phone Troubleshooting (continued)
Summary		Explanation
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		The lighting conditions within the camera’s field of view affect the brightness of
dark		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 5-3for 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.

	Cisco Unified IP Phone 8961, 9951, and 9971 Administration Guide for Cisco Unified Communications Manager 8.5 (SIP)
12-12	OL-20861-01