Cisco Systems 7905G, 7902G, 7912G manual OL-6313-01

Chapter 6 Troubleshooting the Cisco IP Phone

Resolving Known Issues

Table 6-1 Cisco IP Phone Troubleshooting (continued)

Summary	Explanation
Moving a network connection from		If you are powering your phone through the network
the phone to a workstation		connection, you must be 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 prevent this, wait 10 seconds or longer
			after unplugging the cable from the phone. This
			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		By default, the network configuration options are locked to
configuration		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
		“Accessing Network Configuration Settings from a Cisco IP
		Phone” section on page 4-2 for details.
Phone resetting		The phone resets when it loses contact with the
		Cisco CallManager software. This lost connection can be due to
		any network connectivity disruption, including cable breaks,
		switch outages, and switch reboots.
LCD 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
delay		the keys too quickly, some of them might not be recognized.

	Cisco IP Phone Administration Guide for Cisco CallManager 3.3, Cisco IP Phones 7902G/7905G/7912G
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