Power Save Poll (Ps-Poll); Active Mode; Delivery Traffic Indicator Message (Dtim); Scan Modes - Cisco 7925G Deployment Manual

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 7925G 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.

Delivery Traffic Indicator Message (DTIM)

Increasing the DTIM period can also increase the battery life. The Cisco Unified Wireless IP Phone 7925G can use the DTIM
period to schedule wakeup periods to check for broadcast and multicast packets as well as any unicast packets.
For optimal battery life and performance, we recommend setting the DTIM period to "2" with a beacon period of "100 ms".
The DTIM period is a tradeoff between battery life and multicast performance.
Broadcast and multicast traffic will be queued until the DTIM period when there are power save enabled clients associated to
the access point, so DTIM will determine how quickly these packets can be delivered to the client. If using multicast
applications, a shorter DTIM period can be used.

Scan Modes

When using only one access point, select Single Access Point Mode on the phone to reduce scanning and optimize battery life
for phones that do not roam.
When using multiple access points where roaming is required, "Single AP Mode" should not be enabled. Instead use the auto
(default) or continuous scan mode, which will allow for seamless roaming.
Continuous scan mode can be optionally enabled to allow for better location tracking.
Cisco Unified Wireless IP Phone 7925G Deployment Guide 19