Cisco Ip Phone 7800 Series Administration Guide For Cisco Unified Communications Manager - Cisco 7800 series Administrator's Manual

General Troubleshooting Information
Summary
Moving a network connection from
the phone to a workstation
Changing the telephone
configuration
Codec mismatch between the phone
and another device
Sound sample mismatch between the
phone and another device
Loopback condition

Cisco IP Phone 7800 Series Administration Guide for Cisco Unified Communications Manager

206
Explanation
If you power your phone through the network connection, you must
be careful if you decide to unplug the network connection of the phone
and plug the cable into a desktop computer.
The network card in the computer cannot receive power
Caution
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 administrator password settings are locked to prevent
users from making changes that could impact their network
connectivity. You must unlock the administrator password settings
before you can configure them.
See Apply Phone Password, on page 34
Note If the administrator password is not set in common phone
profile, then user can modify the network settings.
The RxType and the TxType statistics show the codec that is used for
a conversation between this Cisco 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. See
on page 185 for details.
The RxSize and the TxSize statistics show the size of the voice packets
that are used in a conversation between this Cisco IP Phone and the
other device. The values of these statistics should match. See
Call Statistics Window, on page 185
A loopback condition can occur when the following conditions are
met:
• The SW Port Configuration option 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 appears in the switch console log:
HALF_DUX_COLLISION_EXCEED_THRESHOLD
To resolve this problem, reenable the port from the switch.
for details.
Display Call Statistics Window,
Display
for details.