Chapter 7 Troubleshooting and Maintenance
General Troubleshooting Tips for the Cisco Unified IP Phone
7-12
Cisco Unified SIP Phone 3911 Administration Guide for Cisco Unified Communications Manager
OL-14029-01
Step 6
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.
Caution
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.
General Troubleshooting Tips for the Cisco Unified
IP Phone
Table 7-1
provides general troubleshooting information for the Cisco Unified IP
Phone.
Table 7-1
Cisco Unified IP Phone Troubleshooting
Summary
Explanation
Poor quality when calling digital cell
phones using the G.729 protocol.
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 cause
IP phones to re-register.
Prolonged broadcast storms (lasting several minutes) on the
voice VLAN cause the IP phones to re-register with another
Cisco Unified Communications Manager server.
Summary of Contents for 3911
Page 4: ......
