TELECOM 247

I cant seem to find anyone selling devices that allow you to lock your
landline phone for outgoing calls.

What I have in mind is a physical lock that you need a key to open -
probably fitted to the wall socket.

Unless anyone knows of different solution to preventing unauthorised calls
being made from a line that has a both a payphone handset and a regular
handset (in a different room) - i.e. I dont want to use a PIN code
arrangement as that will stop valid calls from the payphone (that are being
paid for.)