We removed a Piezo Buzzer from the wall that the telephone line connected to it. The previous owner was elderly so used it for amplification when the phone rang. It had a horrible shrill sound when it rang so we took it off. We've reconnected the wires but now can only receive incoming telephone calls we can't make outgoing calls. We get a line disconnected signal which suggests we've connected the wrong wires.
We have a black cable with 4 wires -yellow -black -white -brown
And a white cable with 4 wires -white -red -blue -green
Which wires are supposed to be connected for the telephone?