This PIC16F84a based repeater DTMF controller is very simple and economical to build. It also gives you hand-on experience of using and programming PIC Micro controllers. Controller measures 10cm X 6 CM and may be housed in your repeater project enclosure.
Controller has 8 OC outputs to drive 8 relays. Outputs are available at 12pin header socket or screw-in terminal blocj where a ribbon cable may be connected. In addition to 8 OC outputs, header/terminal socket also 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 here 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.