Cisco 7841 Installation Manual - Page 36

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Technical Details

Phone Power Requirements

You can power the Cisco IP Phone with external power or with Power over Ethernet (PoE). A separate power supply

provides external power. The switch can provide PoE through the phone Ethernet cable. For more information on your

phone's power requirements, consult your phone's data sheet.

When you install a phone that is powered with external power, connect the power supply before you connect the

Ethernet cable to the phone. When you remove a phone that is powered with external power, disconnect the Ethernet

cable from the phone before you disconnect the power supply.

Table 1: Guidelines for Cisco IP Phone 6800 Series Power

Power Type

External power: Provided through the

external power supply

External power—Provided through the

Cisco IP Phone Power Injector connected to

the 6841 and 6861 phones.

PoE power—Provided by a switch through

the Ethernet cable attached to the 6821,

6851, and 6871 phones.

Table 2: Guidelines for Cisco IP Phone 7800 Series Power

Power Type

External power: Provided through the CP-

PWR-CUBE-3= external power supply

External power—Provided through the

Cisco IP Phone Power Injector

PoE power—Provided by a switch through

the Ethernet cable attached to the phone.

Installation Guide for Cisco IP Phone with Multiplatform Firmware

Guidelines

The 6800 series phones use a custom 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 phone, and supports a maximum

cable length of 100 m between the unpowered switch and the phone.

To ensure uninterruptible operation of the phone, make sure that the

switch has a backup power supply.

Make sure that the Cat OS or IOS version that runs on your switch

supports your intended phone deployment. See the documentation

for your switch for operating system version information.

Guidelines

The Cisco IP Phone uses the CP-PWR-CUBE-3 power supply.

The Cisco IP Phone Power Injector may be used with most Cisco

IP Phones. The phone datasheet identifies if the phone can use the

power injector.

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 phone, and supports a maximum cable

length of 100m between the unpowered switch and the phone.

To ensure uninterruptible operation of the phone, make sure that the

switch has a backup power supply. Make sure that the Cat OS or

IOS version that runs on your switch supports your intended phone

deployment. See the documentation for your switch for operating

system version information.

Phone Power Requirements