Intercom from old corded telephones

Question

I'm experimenting with making a simple intercom from two old corded telephones.

I'm including a buzzer and momentary switch on each end for an incoming call alert.

Below is the circuit I made using two duplex RJ-11 phone jack boxes. This is working.

Inside the jack on the left side of the circuit:

• The red wire is cut and then one end is connected to the "G" wire coming outside of the jack and the other end is connected to the "R" wire coming outside of the jack.
• The green wire inside this jack is left intact inside the jack and only the two red ends and the yellow and black wires are used outside the jack.

Inside the jack on the right side of the circuit:

• The red wire inside the jack is left intact inside the jack
• Only the green, yellow and black wires are used outside this jack.

My question is: how are the two red wire ends and the green wires inside the two jacks connecting in this circuit?

Answer 1

One loose red wire is not really connected as one end is a crimped terminal on an empty post. 9 volts on the red and green would normally power the phones. It seems to me your buzzers will buzz continuously until your series switch's are both made, and short the whole system out.