Resetting Or Restoring The Cisco Unified Ip Phone - Cisco CP-3911 - Unified SIP Phone 3911 VoIP Administration Manual

Chapter 7 Troubleshooting and Maintenance
Table 7-1 Cisco Unified IP Phone Troubleshooting (continued)
Summary
Checking the hook switch contacts.
Checking the LAN cable.
Loopback condition.

Resetting or Restoring the Cisco Unified IP Phone

Cisco Unified SIP Phone 3911 Administration Guide for Cisco Unified Communications Manager
OL-14029-01
Explanation
The hook switch contacts on the phone use a wiping action to
self-clean the contacts. If your phone is not used regularly, dust
and other airborne contaminants may degrade the contact
performance and cause problems with operation. If you have
periods of limited phone usage, you can clean the contacts by
quickly pressing and releasing the hook switch a dozen times.
Make sure that the LAN cable connected to the phone is
positioned properly. The LAN cable should pass out of the side
of the phone between the base and the footstand. If you are
using a cable (such as Cat-5E or Cat-6) with a larger diameter
than the cable that was packaged with your phone, the cable
may cause the phone to tilt forward and force it off-hook. Use
a smaller LAN cable to eliminate this problem.
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 10H
(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.
There are two general methods for resetting or restoring the Cisco Unified IP
Phone:
Performing a Basic Reset, page 7-16
•
Resetting or Restoring the Cisco Unified IP Phone
7-15