Decode DTMF tones to binary outputs

Based on the HT9170 DTMF receiver IC.

3 input configurations – Balanced, unbalanced or microphone (not supplied)

4 binary outputs

Compact PCB 38×30.5mm

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Want a small project that costs less than £5? Our DTMF Detector kit is the answer, complete with the HT9170 DTMF receiver IC.

Three input configurations are possible: un-balanced audio, balanced audio and microphone.


The 4 binary outputs of the HT9170 together with the data valid (DV) strobe, output enable input (OE) and power connections are all available on the 8 pin connector.

If you do not require output enable just link it to the 5V pin. The kit will work on 3V to 5V DC and can also be used with 3.3V logic.


The compact PCB is double sided PTH (plated through hole), 38mm x 30.5mm in size and Gold Plated.

All parts shown in the assembled photo are included as well as 2 x 10K resistors, which you can use for alternative configuration.

The pins can be fitted on the top or on the back of the PCB. Fitting the pins on the back allows fitting the whole assembly onto 0.1” pitch boards like our PIC prototyping boards.


2 x 10K resistors, kit of components, high quality PCB and HT9170 IC.


pdf_symbol[1]Download DTMF Detector Kit PDF   


pdf_symbol[1] Laden Sie DTMF Detektor Bausatz PDF


pdf_symbol[1]HT9170 datasheet


pdf_symbol[1]Amateur Radio TNC connector to DTMF wiring information