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Last Updated: March 26 2021 17:51

DTMF Decoder

Demand for a DTMF decoder to add to existing hardware, such as amateur repeaters, to add remote control of various functions continues to be high.

I have therefore produced an upgraded version of my original DTMF decoder taking advantage of more easily available SMT components and also improving functionality.

DTMF Controller
Click image to view full size.

This new DTMF decoder is listed here as DTMF decoder Mk3.

The use of SMT has allowed the size of the PCB to shrink to 58.5 x 29 x 5mm whilst adding the ability to program a 4 digit security pin, provision of DTMF to serial conversion and provision to switch outputs from RS232 command.

8 x open collector outputs, and a 9600bps RS232 port are provided.
Power supply is 6 to 15v at 50mA.
An audio input at high impedance of at least 50mV p-p is required.

DTMF3 pcb overlay showing connection details

The DTMF Mk3 is supplied as a built and tested unit ready for integration into your hardware at a price of £37.50

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