Cisco 3905 Administration Manual page 104

General Troubleshooting Information
Summary
Moving a network connection from the phone
to a workstation.
Changing the telephone configuration.
Phone resetting.
Codec mismatch between the phone and another
device.
Sound sample mismatch between the phone and
another device.
Cisco Unified SIP Phone 3905 Administration Guide for Cisco Unified Communications Manager 8.6 (SIP)
90
Troubleshooting and Maintenance
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.
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 Configuration Menus, on page 35
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.
The RxType and the TxType statistics show the codec that
is being used for a 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.
The RxSize and the TxSize statistics show the size of the
voice packets that are being used in a conversation between
this Cisco Unified IP phone and the other device. The
values of these statistics should match.
for details.