G1SLE.com - Projects in Amateur Radio |
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Last Updated: March 26 2021 17:51
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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.
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
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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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