INFORMATION ABOUT RING GENERATOR 34 V
Please see the circuit diagram.
There is a switch S on the mains cord. S2 turns the signal off. The frequency is
controlled by S3. The value of frequency is 25 or 50 Hertz. You're adjusting the
ring signal amplitude by the 10 kilo ohm potentiometer.
When you want to test the ring signal function of a phone, you should connect a
suitable resistor in series with the telephone. Please see the connection diagram
below.
The receiver will be hung up during the test. If the phone works, it will be ringing
at the maximum value set of ring signal.