Cisco Unified 6921 Manuel d'administration - Page 5

Chapter

Power Outage

Your accessibility to emergency service through the phone is dependent on the phone being powered. If

there is an interruption in the power supply, Service and Emergency Calling Service dialing will not

function until power is restored. In the case of a power failure or disruption, you may need to reset or

reconfigure equipment before using the Service or Emergency Calling Service dialing.

For related information about power, refer to the documents shown in

provide information about the following topics:

•

Table 2-2

Document Topics

Cisco Unified IP Phone Power

Injector

PoE Solutions

Cisco Catalyst Switches

Integrated Service Routers

Cisco IOS Software

Configuration files for a phone are stored on the TFTP server and define parameters for connecting to

Cisco Unified CM. In general, any time you make a change in Cisco Unified CM that requires the phone

to be reset, a change is automatically made to the phone's configuration file.

Configuration files also contain information about which image load the phone should be running. If this

image load differs from the one currently loaded on a phone, the phone contacts the TFTP server to

request the required load files.

A phone accesses a default configuration file named XmlDefault.cnf.xml from the TFTP server when

the following conditions exist:

•

In addition, if the device security mode in the configuration file is set to Authenticated and the CTL file

on the phone has a valid certificate for Cisco Unified CM, the phone establishes a TLS connection to

Cisco Unified CM. Otherwise, the phone establishes a TCP connection.

Cisco Unified IP Phone 6921, 6941, 6945, and 6961 Administration Guide for Cisco Unified Communications Manager 8.6 (SCCP and SIP)

OL-24567-01

Cisco switches that work with the Cisco Unified IP Phone 6921, 6941, 6945, and 6961

The Cisco IOS releases that support bidirectional power negotiation

Other requirements and restrictions regarding power