How can i get my handset to speak with the caller?

I have a BT4600 system with 2 handsets. the batteries are fine in the handsets.
however one of the handsets i can hear the caller ok. but the caller cannot hear me speaking. The other handset works fine. how do i get the handset to work properly?
john, January 2023

Check the mute/privacy button hasn't been pressed or is stuck down.
Failing that it sounds like a duff handset, unless the manual comes up with anything.
Should be plenty on eBay etc.
If you're patient, there might be something comes up for free on Freecycle etc or NextDoor websites

Ghfdh, January 2023