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Cisco Unified IP Phone 7960G/7940G Administration Guide for Cisco Unified Communications Manager 7.0 (SCCP)
OL-15498-01
Chapter 8 Troubleshooting and Maintenance
Cisco Unified IP Phone Resets Unexpectedly
Note • When you remove a phone from the Cisco Unified Communications Manager database, its
configuration file is deleted from the Cisco
Unified Communications Manager TFTP server. The
phone’s directory number or numbers remain in the Cisco
Unified Communications Manager
database. They are called “unassigned DNs” and can be used for other devices. If unassigned DNs
are not used by other devices, delete them from the Cisco
Unified Communications Manager
database. You can use the Route Plan Report to view and delete unassigned reference numbers.
Refer to Cisco
Unified Communications Manager Administration Guide for more information.
• Changing the buttons on a phone button template, or assigning a different phone button template to
a phone, may result in directory numbers that are no longer accessible from the phone. The directory
numbers are still assigned to the phone in the Cisco
Unified Communications Manager database, but
there is no button on the phone with which calls can be answered. These directory numbers should
be removed from the phone and deleted if necessary.
Symptom: Cisco Unified IP Phone Unable to Obtain IP Address
If a phone is unable to obtain an IP address when it starts up, the phone may be not be on the same
network or VLAN as the DHCP server, or the switch port to which the phone is connected may be
disabled.
Make sure that the network or VLAN to which the phone is connected has access to the DHCP server,
and make sure that the switch port is enabled.
Cisco Unified IP Phone Resets Unexpectedly
If users report that their phones are resetting during calls or while idle on their desk, you should
investigate the cause. If the network connection and Cisco
Unified Communications Manager
connection are stable, a Cisco
Unified IP Phone should not reset on its own.
Typically, a phone resets if it has problems connecting to the Ethernet network or to
Cisco
Unified Communications Manager. These sections can help you identify the cause of a phone
resetting in your network:
• Verifying Physical Connection, page 8-6
• Identifying Intermittent Network Outages, page 8-7
• Verifying DHCP Settings, page 8-7
• Checking Static IP Address Settings, page 8-7
• Verifying Voice VLAN Configuration, page 8-7
• Verifying that the Phones Have Not Been Intentionally Reset, page 8-8
• Eliminating DNS or Other Connectivity Errors, page 8-8
Verifying Physical Connection
Verify that the Ethernet connection to which the Cisco Unified IP Phone is connected is up. For example,
check if the particular port or switch to which the phone is connected is down.