Cisco 7911G - IP Phone VoIP User Manual

Chapter 9 Troubleshooting and Maintenance
General Troubleshooting Tips
9-18
Cisco Unified IP Phone 7906G and 7911G for Cisco Unified Communications Manager 6.0
OL11954-01
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) delay.
When you are on a call that requires
keypad input, if you press the keys too
quickly, some of them might not be
recognized.
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_T
HRESHOLD
To resolve this problem, re-enable the
port from the switch.
Table 9-2 Cisco Unified IP Phone Troubleshooting (continued)
Summary Explanation

Cisco 7911G - IP Phone VoIP Specifications

General

Brand	Cisco
Model	7911G - IP Phone VoIP
Category	IP Phone
Language	English