A transistor switch has been added to the input of CPS43, allowing it to be controlled by simple logic levels. Dial up your phone from anywhere in the world, input your pin number then turn on or off any of 4 relays. Use the relays to control any devices you have in your house or office. The pin number is set by 4 on-board BCD rotary switches. The standard line impedance termination can be customized by the user for their own particular country if they want to get better impedance matching.
All source code comes on floppy disk with the kit.
The LEDs are for testing to give a visual indication that the relays are working. It is your responsibility to adhere to any applicable laws or rules regarding the attachment of this device to a telephone line. Both types of switches are built onto the one PCB so you can see and explore how each type works. Pulses from a 555 setup as an astable oscillator are used to rough position the motor. Switch to manual single-step mode for final positioning using a tact switch.