Uploaded August 2022 | Updated September 2026, 2 weeks ago

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PCBWay Supports High Precision Advanced PCBs: pcbway.com
This DTMF decoder pcb uses the MT8870 IC and connects to a phone line, allowing an audio path for the decoder to listen for DTMF tone pairs.
When a valid DTMF signal is decoded, an Arduino can interpret the key press.

Bare PCBs at PCBWay: pcbway.com/project/shareproject/DTMF_Decoder_Phone_Interface_8aa3586d.html
Sketch/Schematic: github.com/GadgetReboot/DTMF_Decoder
MT8870 Datasheet: http://www.da.isy.liu.se/vanheden/pdf/mt8870.pdf

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