Chapter 2 Preparing to Install the Cisco Unified IP Phone on Your Network
Providing Power to the Phone
2-6
Cisco Unified IP Phone 7970G/7971G-GE Administration Guide for Cisco Unified Communications Manager 6.1
OL-14626-01
Phone Power Consumption and Display Brightness
The power consumed by a phone depends on its power configuration. See
Table 2-1
for a power configuration overview. See
Table 2-2
for the maximum
power consumed by a phone for each configuration option and the correlating
phone screen brightness level.
Note
Power consumption values shown in the table include power losses in the cable
that connects the phone to the switch.
Table 2-2
Power Consumption and Display Brightness for Power Configurations
Phone Model
Power Configuration
Max. Power
Consumed
from a Switch
Phone
Screen
Brightness
Cisco Unified
IP Phone
7970G
Cisco prestandard PoE from a switch that supports a
maximum of 7 W power per port, with bidirectional
power negotiation enabled
6.3 W
Approx. 1/2
Cisco prestandard PoE from a Cisco Switch that
supports 7 W or 15.4 W power per port, without
bidirectional power negotiation
6.3 W
Approx. 1/2
IEEE 802.3af Class 3 power from a Cisco switch,
without bidirectional power negotiation
6.3 W
Approx. 1/2
IEEE 802.3af Class 3 power from a third-party switch
6.3 W
Approx. 1/2
IEEE 802.3af Class 3 power from a Cisco switch, with
bidirectional power negotiation enabled
10.25 W
Full
1
Cisco prestandard PoE from a Cisco Switch that
supports 15.4 W power per port, with bidirectional
power negotiation enabled
10.25 W
Full
External power
—
Full
Cisco Unified
IP Phone
7971G-GE
IEEE 802.3af Class 3 power from a Cisco switch (with
or without bidirectional power negotiation enabled) or
from a third-party switch
15.4 W
Near full
External power
—
Full
Summary of Contents for 7970G - IP Phone VoIP
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