The theory is that if you short out pins 3, 6, & 9 on the bottom of the
phone you can use it as a listening bug by hiding it in a room and then
calling the number. I can get it to work using a hands free kit, BUT I would
prefer to get it working so that the phone's microphone picks up the
conversation instead. If the phone were ever to be accidentally stumbled
upon, it would look less suspicious if it were just the phone on it's own
without a hands free kit connected to it.

Yes, I know it's an old phone, but it has a very long standby and talk time,
and therefore makes it ideal for what I am needing it for. ie, to catch my
wife out who I suspect is having an affair whilst I am away on business for
days on end.

All the sites I've googled say the same thing, either short circuit 3, 6, &
9, or short-circuit the left middle and right pins on the bottom of the
phone with all connections touching each other. Phone is set to auto answer,
which is does, it's just that the microphone isn't activating.

Has anyone ever managed to get this to work without a handsfree kit? Any
useful advice gladly accepted.

TIA.