Table 8: Power Consumption and Display Brightness for Power Configurations
Phone screen brightness
Max. power
consumed from a
switch
Power configuration
Phone model
Full
12 W
IEEE 802.3af Class 3 power from a
Cisco switch, with bidirectional power
negotiation enabled
Cisco Unified
IP Phone
7975G, 7965G,
7945G
Full
—
External power
Near full
15.4 W
IEEE 802.3af Class 3 power from a
Cisco switch (with or without
bidirectional power negotiation
enabled) or from a third-party switch
Cisco Unified
IP Phone
7971G-GE
Full
—
External power
Approx. 1/2
6.3 W
Cisco prestandard PoE from a switch
that supports a maximum of 7 W
power per port, with bidirectional
power negotiation enabled
Cisco Unified
IP Phone
7970G
Approx. 1/2
6.3 W
Cisco prestandard PoE from a Cisco
Switch that supports 7 W or 15.4 W
power per port, without bidirectional
power negotiation
Approx. 1/2
6.3 W
IEEE 802.3af Class 3 power from a
Cisco switch, without bidirectional
power negotiation
Approx. 1/2
6.3 W
IEEE 802.3af Class 3 power from a
third-party switch
Full (see note)
10.25 W
IEEE 802.3af Class 3 power from a
Cisco switch, with bidirectional power
negotiation enabled
Full
10.25 W
Cisco prestandard PoE from a Cisco
Switch that supports 15.4 W power
per port, with bidirectional power
negotiation enabled
Full
—
External power
Cisco Unified IP Phone 7975G, 7971G-GE, 7970G, 7965G, and 7945G Administration Guide for Cisco Unified
Communications Manager 9.0 (SCCP and SIP)
33
Cisco Unified IP Phones and Telephony Networks
Phone Power Consumption and Display Brightness