Featuring two different types of telephone ring generators, two line "in-use" indicator circuits, and an audio interface circuit.
This page features the circuit diagrams and information for the following circuits:
- Telephone Ring Generator Using Switching Supply
- This circuit will ring at telephone at defined intervals - as set by the timing components of the circuit
- Telephone Ring Generator Using Small Power Transformer
- This circuit will also ring at telephone at defined intervals
- Telephone In-Use Indicator
- Circuit checks the telephone line to determine whether or not it is in use. Lights an LED (Light Emitting Diode).
- Telephone In-Use Relay Controller
- Same as previous, however it uses a relay so that you can do more than just light an LED.
- Telephone Audio Interface
- Allows for the extraction of audio from a telephone line
- Telephone Ring Generator