Cisco Systems 8961 manual Displaying these statistics, 12-11

Chapter 12 Troubleshooting and Maintenance

General Troubleshooting Tips

Table 12-2	Cisco Unified IP Phone Troubleshooting (continued)
Summary			Explanation
Moving a network connection from the			If you are powering your phone through the network connection, you must be
phone to a workstation			careful if you decide to unplug the phone’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 phone before
				plugging it into a computer. This delay gives the switch enough time
				to recognize that there is no longer a phone on the line and to stop
				providing power to the cable.
Changing the telephone configuration			By default, the network configuration options are locked to prevent users from
			making changes that could impact their network connectivity. You must unlock
			the network configuration options before you can configure them. See the
			“Unlocking and Locking Options” section on page 7-3for details.
Phone resetting			The phone resets when it loses contact with the Cisco Unified Communications
			Manager software. This lost connection can be due to any network connectivity
			disruption, including cable breaks, switch outages, and switch reboots.
Phone display issues		If the display appears to have rolling lines or a wavy pattern, it might be
			interacting with certain types of older fluorescent lights in the building. Moving
			the phone away from the lights, or replacing the lights, should resolve the
			problem.
Dual-Tone Multi-Frequency (DTMF)			When you are on a call that requires keypad input, if you press the keys too
delay			quickly, some of them might not be recognized.
Codec mismatch between the phone and			The RxType and the TxType statistics show the codec that is being used for a
another device			conversation between this Cisco Unified IP phone and the other device. The
			values of these statistics should match. If they do not, verify that the other device
			can handle the codec conversation, or that a transcoder is in place to handle the
			service.
			See the “Call Statistics Screen” section on page 10-11for information about
			displaying these statistics.
Sound sample mismatch between the			The RxSize and the TxSize statistics show the size of the voice packets that are
phone and another device			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 10-11for information about
			displaying these statistics.
Gaps or delays in voice calls			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 10-11for information about
			displaying these statistics.

	Cisco Unified IP Phone 8961, 9951, and 9971 Administration Guide for Cisco Unified Communications Manager 8.5 (SIP)
OL-20861-01		12-11