Power Outage; Power Guidelines - Cisco 7931G - Unified IP Phone VoIP Administration Manual

Chapter 2 Preparing to Install the Cisco Unified IP Phone on Your Network

Power Outage

Power Guidelines

Table 2-1 Guidelines for Powering the Cisco Unified IP Phones 7931G
Power Type
External power—
Provided through a Cisco
external power supply.
External power—
Provided through the
Cisco Unified IP Phone
Power Injector.
PoE power—Provided by
a switch through the
Ethernet cable attached to
the phone.
Cisco Unified IP Phone 7931G Administration Guide for Cisco Unified Communications Manager 6.0
OL-12457-01
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.
Table 2-1 provides guidelines that apply to external power and to PoE power for
the Cisco Unified IP Phones 7931G.
Guidelines
The CP-PWR-CUBE-3 external power supply may be used with the
Cisco Unified IP Phones 7931G.
The Cisco Unified IP Phone Power Injector may be used with any
Cisco Unified IP Phone. Functioning as a midspan device, the injector
delivers inline power to the attached phone. The Cisco Unified IP Phone
Power Injector is connected between a switch port and the IP Phone, and
supports a maximum cable length of 100m between the unpowered switch
and the phone.
The Cisco Unified IP Phones 7931G supports IEEE 802.3af Power
•
over Ethernet.
To ensure uninterruptible operation of the phone, make sure that the
•
switch has a backup power supply.
Make sure that the CatOS or IOS version running on your switch
•
supports your intended phone deployment. Refer to the documentation
for your switch for operating system version information.
Providing Power to the Phone
2-5