Sony SPP-A9171 - Manual (Page 32)

32 US Telephone Features
Paging
You can page the handset from the base unit.
Note that you cannot page if the handset is in use.
To Page
Press (HANDSET LOCATOR).
The handset rings for about one
minute.
To stop ringing, press (TALK) or
(OFF) on the handset.
Tip
You can page the handset even when its RING switch is set to OFF.