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DTMF Controller

I have built a Fox Delta FD-RPC2A DTMF controller for my Repeater project.

The PDF File for the project is Here.


This is the discritpion from the Fox Delta website about the FD-RPC2 - A

"This PIC16F84a based repeater (DTMF) controller is very simple & economical to build. It also gives you hand-on experience of using & programming PIC Micro controllers. Controller measures 10cm X 6 CM and may be housed in your repeater project enclosure

Controller here is based on a design idea from Dave Robinson WW2R who has provided necessary software & hardware information on this controller.

Design of this Controller is based on MT8870 DTMF receiver, a Microchip 16F84A Micro-Controller and an ULN2803A relay driver .

Controller has 8 Open Collector outputs to drive 8 relays. Outputs are available at 12pin header socket or screw-in terminal block where a ribbon cable may be connected. In addition to 8 Open Collector outputs, the header and terminal socket provides 12V, Ground & 5V (for pull-ups only).

Controller is without relays & is designed to be accommodated within an existing project, where DTMF control is required. It will drive 5/12V relays of any type, without problems.

Firmware for PIC is available for download in .ASM file with password 1234 which may be changed at the time of programming the PIC. This firmware was tested & controller worked perfectly without missing any command.

Another version of Firmware which will "remember" the last status of the relay's after a power failure, is also available but is un-tested."


 8c12vrelayoc p04

I have purchased this relay board from eBay to interface the DTMF controller to my repeater and other devices.

  • This is a 12V Relay interface board and it can be controlled directly by a wide range of microcontrollers such as Arduino AVR, PIC, DSP, ARM, ARM, MSP430, and so on.
  • 8-Channel Relay interface board,
  • Each 12V Relay requires 20mA driving current,
  • Indication LED for each Relay,
  • Standard interface that can be controlled directly byArduino AVR, PIC, DSP, ARM, ARM, MSP430, TTL and so on.

And at $17.00 delivered, it's a bargin.



Last Updated on Friday, 26 November 2021 19:35