Making phones ring on a closed circuit / intercom system

[Owain]

I will also post in a new thread a 10-line telephone exchange using 22 relays

[trainman]

I took two WE 307 which are wired for local battery operation and connected them together. Each phone has it's own 3 volt battery and magneto. Works great. Best part, no electricity is used. Battery and hand generated ringing voltage. NEver got around to adding more phones.