Table 4: Guidelines for Cisco IP Phone Power
Guidelines
Power Type
The phones use a custom power supply.
External power: Provided through the external power
supply
The Cisco IP Phone Power Injector may be used with
the phones.
Functioning as a midspan device, the injector delivers
inline power to the attached phone. The Cisco IP
Phone Power Injector connects between a switch port
and the IP Phone, and supports a maximum cable
length of 100 m between the unpowered switch and
the IP phone.
External power—Provided through the Cisco IP Phone
Power Injector connected to the Cisco IP Phone 6841
Multiplatform Phones and Cisco IP Phone 6861
Multiplatform Phones.
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 that runs on
your switch supports your intended phone deployment.
See the documentation for your switch for operating
system version information.
PoE power—Provided by a switch through the
Ethernet cable attached to the Cisco IP Phone 6821
Multiplatform Phones and Cisco IP Phone 6851
Multiplatform Phones.
The documents in the following table provide more information on the following topics:
• Cisco switches that work with Cisco IP Phones
• Cisco IOS releases that support bidirectional power negotiation
• Other requirements and restrictions about power
URL
Document topics
http://www.cisco.com/c/en/us/solutions/
enterprise-networks/power-over-ethernet-solutions/
index.html
PoE Solutions
http://www.cisco.com/c/en/us/products/switches/
index.html
Cisco Catalyst Switches
http://www.cisco.com/c/en/us/products/routers/
index.html
Integrated Service Routers
http://www.cisco.com/c/en/us/products/
ios-nx-os-software/index.html
Cisco IOS Software
Power Outage
Your access to emergency service through the phone requires that the phone receive power. If a power
interruption occurs, service or emergency calling service dialing does not function until power is restored. If
a power failure or disruption occurs, you may need to reset or reconfigure the equipment before you can use
service or emergency calling service dialing.
Cisco IP Phone 6800 Series Multiplatform Phones Administration Guide
15
About the Cisco IP Phone
Power Outage
