How do I wire two telephone handsets together with a 9v battery to ring out wires?

[twoskinsoneman]

I have seen technicians with two telephone handsets each with alligator clips on them. The hook one telephone handset on a pair of wires and the other on the other end and can talk. A 9v battery is taped to one handset. I bought two payphone handsets thinking I could do the same thing but have not got it working. Are pay phone handsets different? Does anyone have a wiring diagram of the way to wire the battery into the handsets?