General Troubleshooting Tips For The Cisco Unified Ip Phone - Cisco CP-3911 - Unified SIP Phone 3911 VoIP 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 3911 Administration Guide for Cisco Unified Communications Manager
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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 Communications Manager, 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 Communications Manager server.
Chapter 7 Troubleshooting and Maintenance
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