Key Expansion Module Power Information
If you use a key expansion module with your IP phone, then Power over Ethernet (PoE) is enough to power
your expansion modules. But, your phone must have an IP address in order to charge the expansion module.
A power cube is needed for smartphone or tablet charging when your key expansion module is attached.
A key expansion module uses 48V DC, 5W per module. If you are charging a smartphone or a tablet, note
the following:
• Side USB: Up to 500mA/2.5W charging
• Back USB: Fast charging, Supports up to 2.1A/10.5W charging
Table 6: Power-Supply Compatibility for Cisco IP Phone 8800 Key Expansion Module
Cisco IP Phone Power Cube 4802.3at PoE802.3af Power over Ethernet
(PoE)
Configuration
YesYesYes8851 with 1 key expansion
module
YesNo
See the third note below
No8851with 2 key expansion
modules
YesYesNo8861 with 1 key expansion
module
YesYes
See the first note below
No8861 with 2 key expansion
modules
YesYes
See the first note below
No8861 with 3 key expansion
modules
• The fast-charging feature on the back USB does not work when more than one key expansion module
is attached to a Cisco IP Phone 8861 using 802.3at PoE.
• The fast-charging feature on the back USB doesn’t work when more than one key expansion module is
attached to a Cisco IP Phone 8861, unless Cisco Universal PoE (UPoE) is used.
• Cisco IP Phone 8851 with 2 key expansion modules works on 802.3at PoE only with v08 or later hardware.
You can find the phone version information on the lower back of the phone as part of the TAN and PID
label. Version information is also located on the individual phone packaging.
Note
Cisco IP Phone Accessories
15
Cisco IP Phone Accessories
Key Expansion Module Power Information