Specifications

Cisco Unified Wireless IP Phone 7921G Series Deployment Guide 21
Idle
150
200
If the access point does not support CCX or proxy ARP is not enabled, then the idle battery life will be up to fifty percent less.
See the “Configuring Proxy ARP” section for more information.
Protocols
Unscheduled Auto Power Save Delivery (U-APSD)
The Cisco Unified Wireless IP Phone 7921G will use U-APSD (Unscheduled Auto Power Save Delivery) for power save when
in idle mode or when a phone call is active if WMM is enabled, where U-APSD is supported.
U-APSD helps optimize battery life.
Below is a sample packet sequence when using U-APSD.
Power Save Poll (PS-POLL)
If Wi-Fi MultiMedia (WMM) is disabled, which will disable U-APSD support, or U-APSD support is not available on the
access point, then the Cisco Unified Wireless IP Phone 7921G will use PS-POLL for power save when in idle mode and when a
phone call is active.
Below is a sample packet sequence when using PS-POLL.
Active Mode
If the “Call Power Save Mode” is set to “None”, then the phone will use active mode and no power save will be used, which
will reduce the battery life.