Specifications

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Cisco Unified IP Phone 7931G Administration Guide for Cisco Unified Communications Manager 8.0 (SCCP and SIP)
OL-20798-01
Chapter 2 Preparing to Install the Cisco Unified IP Phone on Your Network
Providing Power to the Phone
Power Guidelines
Table 2-1 provides guidelines that apply to external power and to PoE power for the Cisco Unified IP
Phones 7931G.
Obtaining Additional Information about Power
For related information about power, refer to the documents shown in Table 2-2. These documents
provide information about these topics:
• Cisco switches that work with the Cisco Unified IP Phones
• The Cisco IOS releases that support bidirectional power negotiation
• Other requirements and restrictions regarding power
Table 2-1 Guidelines for Powering the Cisco Unified IP Phones 7931G
Power Type Guidelines
External power— Provided
through a Cisco external power
supply.
The CP-PWR-CUBE-3 external power supply may be used with the Cisco Unified IP
Phones 7931G.
External power—Provided
through the Cisco Unified IP
Phone Power Injector.
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.
PoE power—Provided by a switch
through the Ethernet cable
attached to 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.
Table 2-2 Related Documentation for Power
Document
Topics URL
Cisco Unified
IP Phone
Power Injector
http://www.cisco.com/en/US/products/hw/phones/ps379/prod_installation_guides_list.html
PoE Solutions http://www.cisco.com/en/US/netsol/ns340/ns394/ns147/ns412/networking_solutions_package.html
Cisco Catalyst
Switches
http://www.cisco.com/en/US/products/hw/switches/ps708/tsd_products_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