The SLIC has an audio output. Let's hook that up to the mic input of the laptop. As wikipedia shows, there are different pinouts standards for a TRRS 3.5mm audio jack. In other words, there's no standard pinout. Use a DMM to find out what pinout your laptop is using. My Acer has the following pinout:
- Tip = Left out
- Ring1 = Right out
- Ring2 = GND
- Sleeve = Mic in
In Ubuntu Linux, 5s of audio can easily be recorded by:
arecord -d 5 DTMF_0123456789.wav
To play back the file:
The microphone level might need some tuning.
Decode the DTMF-audio with:
multimon -a DTMF -t wav DTMF_0123456789.wav multimod (C) 1996/1997 by Tom Sailer HB9JNX/AE4WA available demodulators: POCSAG512 POCSAG1200 POCSAG2400 EAS AFSK1200 AFSK2400 AFSK2400_2 HAPN4800 FSK9600 DTMF ZVEI CCIR SCOPE Enabled demodulators: DTMF sox WARN sox: Option `-s' is deprecated, use `-e signed-integer' instead. sox WARN sox: Option `-2' is deprecated, use `-b 16' instead. DTMF: 0 DTMF: 1 DTMF: 2 DTMF: 3 DTMF: 4 DTMF: 5 DTMF: 6 DTMF: 7 DTMF: 8 DTMF: 9
Decoding works perfectly.
Alternative DTMF decoders
- MT8870 DTMF Audio Decoder LCD 1602 Display Module for Fixed telephone mobile phone keypad Key value shows smart home
- wholesale 1pcs MT8870 DTMF Voice decoding module phone module
- You could also download a DTMF decoder for your smartphone from Google Play.