Cisco 8800 Series Administration Manual page 33

About the Cisco IP Phone
• Cisco switches that work with Cisco IP Phones
• Cisco IOS releases that support bidirectional power negotiation
• Other requirements and restrictions about power
Table 5: Additional Information
Document topics
PoE Solutions
UPoE
Cisco Catalyst Switches
Integrated Service Routers
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.
Power Reduction
You can reduce the amount of energy that the Cisco IP Phone consumes by using Power Save mode.
Power Save
Power Negotiation Over LLDP
The phone and the switch negotiate the power that the phone consumes. Cisco IP Phone operates at multiple
power settings, which lowers power consumption when less power is available.
After a phone reboots, the switch locks to one protocol (CDP or LLDP) for power negotiation. The switch
locks to the first protocol (containing a power Threshold Limit Value [TLV]) that the phone transmits. If the
system administrator disables that protocol on the phone, the phone cannot power up any accessories because
the switch does not respond to power requests in the other protocol.
In Power Save mode, the backlight on the screen is not lit when the phone is not in use. The phone
remains in Power Save mode until the user lifts the handset or presses any button. Set up each phone to
enable or disable Power Save settings.
URL
http://www.cisco.com/c/en/us/solutions/
enterprise-networks/power-over-ethernet-solutions/
index.html
http://www.cisco.com/c/en/us/solutions/
enterprise-networks/upoe/index.html
http://www.cisco.com/c/en/us/products/switches/
index.html
http://www.cisco.com/c/en/us/products/routers/
index.html
http://www.cisco.com/c/en/us/products/
ios-nx-os-software/index.html
Cisco IP Phone 8800 Series Multiplatform Phones Administration Guide
Power Outage
17