Dual Tone Multi Frequency signaling, commonly referred to as DTMF, is mainly used for phone dialing systems. But this isn’t the only use for DTMF signaling. Another common use is security access systems. In this post, I’ll be covering how to decode DTMF using MultiMon-NG. SoX will be used to record the DTMF signals generated on cell phones and keyless entry systems. I’ll be using a high gain directional microphone with a secondary microphone to cancel out background noise. SoX … Continue reading Decoding DTMF with MultiMon-NG