General Troubleshooting Tips For The Cisco Unified Ip Phone - Cisco 3951 Administration Manual

General Troubleshooting Tips for the Cisco Unified IP Phone

Step 6
Caution
General Troubleshooting Tips for the Cisco Unified
IP Phone
Table 7-1 Cisco Unified IP Phone Troubleshooting
Summary
Poor quality when calling digital cell
phones using the G.729 protocol.
Prolonged broadcast storms cause
IP phones to re-register.
Cisco Unified SIP Phone 3951 Administration Guide for Cisco Unified CallManager 5.1
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Power cycle the phone:
If the phone receives power from an external power source, unplug the
•
Ethernet cable from the Network port on the phone, then unplug the power
supply from the DC adaptor port on the phone. Next, reconnect the power
supply and then reconnect the Ethernet cable.
Always unplug the upstream Ethernet cable from the phone before unplugging the
power supply. Unplugging the power supply before unplugging the upstream
Ethernet cable could result in a service interruption on the network.
If the phone receives inline power, unplug the cable from the Network port on
•
the phone and then plug it back in.
Table 7-1 provides general troubleshooting information for the Cisco Unified IP
Phone.
Explanation
In Cisco Unified CallManager, you can configure the network
to use the G.729 protocol (the default is G.711). When using
G.729, calls between an IP phone and a digital cellular phone
will have poor voice quality. Use G.729 only when absolutely
necessary.
Prolonged broadcast storms (lasting several minutes) on the
voice VLAN cause the IP phones to re-register with another
Cisco Unified CallManager server.
Chapter 7 Troubleshooting and Maintenance
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