Cisco 7970G Administration Guide - Page 250

General Troubleshooting Tips Chapter 9 Troubleshooting and Maintenance Table 9-2 Cisco Unified IP Phone Troubleshooting (continued) Summary Moving a network connection from the phone to a workstation Explanation If you are powering your phone through the network 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 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 LCD display issues Dual-Tone Multi-Frequency (DTMF) delay 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 4-4 for details. 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. When you are on a call that requires keypad input, if you press the keys too quickly, some of them might not be recognized. 9-16 Cisco Unified IP Phone 7970G/7971G-GE Administration Guide for Cisco Unified Communications Manager 6.1 OL-14626-01