Sony IT-ID20 Mode D'emploi page 9

Choose the dialing mode
For the telephone to work properly, select an appropriate dialing
mode (tone or pulse) with a ball-point pen, etc.
Depending on your dialing system, set the DIAL MODE switch as
follows:
If your dialing system is
Tone
Pulse
If you aren't sure of your dialing system
Make a trial call with the DIAL MODE switch set to T.
If the call connects, leave the switch as is; otherwise, set to P.
DIAL MODE
switch
Set the switch to
T
P
US
9
Getting Started