Cisco 7920 Phone Manual page 22

Figure 1-2 Charging the Phone Battery
Tips
The phone detects when the battery power level
•
is low and displays the warning message,
"Battery Low" with the warning tone specified in
your active user profile.
The standard battery provides up to 3.5 hours of
•
talk time or up to 21 hours of standby time.
The extended battery provides up to 4.25 hours
•
of talk time or up to 30 hours of standby time.
14 78-16888-01