Siemens ROLMphone 120 Series User Manual page 155

The other party cannot hear you when you are using the
speakerphone, though everything else works.
Verify that your phone is equipped with a speakerphone (speaker and
microphone). Check the phone name on the label underneath the
phone. RP120 models and the RP240 Basic do not have a microphone,
and you must use the handset to speak to the other
party.
The phone does not ring when called, though everything else
works.
Verify that the phone is not forwarded. If the phone is forwarded, the
line key will flicker. See "Forwarding" on page 5–1 for information on
forwarding and cancelling forwarding.
Also verify whether the phone is not in Do Not Disturb mode. To
cancel Do Not Disturb, press the Do Not Disturb (DND) key until its
status light turns off.
Your speakerphone turns on and off when the other party is
talking.
Noisy environments may cause the speakerphone to behave as if you
are talking, thereby cutting off the other party. If you cannot eliminate
the background noise, try using the Mute feature while the other
person is talking, and then deactivate it when you want to talk to them.
(See "Muting the Speakerphone" on page 2–13.)
Help! B-3