Cisco IP Phone 7942G - Manual (Page 5)

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Cisco Unified IP Phone 7962G and 7942G Administration Guide for Cisco Unified Communications Manager 6.1(3)
OL-17679-01
Chapter 2 Preparing to Install the Cisco Unified IP Phone on Your Network
Understanding Phone Configuration Files
Obtaining Additional Information about Power
For related information about power, refer to the documents shown in Table 2-2 . These documents
provide information about the following topics:
• Cisco switches that work with the Cisco Unified IP Phone 7962G and 7942G
• The Cisco IOS releases that support bidirectional power negotiation
• Other requirements and restrictions regarding power
Understanding Phone Configuration Files
Configuration files for a phone are stored on the TFTP server and define parameters for connecting to
Cisco Unified Communications Manager. In general, any time you make a change in Cisco Unified
Communications Manager 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. (These files are digitally signed to ensure the authenticity of the files’
source.)
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 Communications Manager, the phone establishes
a TLS connection to Cisco Unified Communications Manager. Otherwise, the phone establishes a TCP
connection. For SIP phones, a TLS connection requires that the transport protocol in the phone
configuration file be set to TLS, which corresponds to the transport type in the SIP Security Profile in
Cisco Unified Communications Manager Administration.
Note If the device security mode in the configuration file is set to Authenticated or Encrypted, but the phone
has not received a CTL file, the phone will continuously try to obtain a CTL file, so that it can register
securely.
If you configure security-related settings in Cisco Unified Communications Manager Administration,
the phone configuration file will contain sensitive information. To ensure the privacy of a configuration
file, you must configure it for encryption. For detailed information, refer to the “Configuring Encrypted
Table 2-2 Related Documentation for Power
Document Topics URL
Cisco Unified IP Phone Power
Injector http://www.cisco.com/en/US/products/ps6951/index.html
PoE Solutions http://www.cisco.com/en/US/netsol/ns340/ns394/ns147/ns412/inde
x.html
Cisco Catalyst Switches http://www.cisco.com/en/US/products/hw/switches/ps708/tsd_prod
ucts_support_series_home.html
Integrated Service Routers http://www.cisco.com/en/US/products/hw/routers/index.html
Cisco IOS Software http://www.cisco.com/en/US/products/sw/iosswrel/products_ios_
cisco_ios_software_category_home.html