AJMRTC 2Pcs MT8870 DTMF Decoder Module, Telephone Audio Tone Decoding Board, 3.5mm Audio Jack DTMF Signal Recognition Module Compatible with Arduino, STM32, Raspberry Pi for Dial Control Projects

AJMRTC MT8870 DTMF decoder module is a dedicated dual-tone multi-frequency audio decoding board for electronic makers and embedded developers. It integrates the MT8870 DTMF receiver chip, which contains built-in band-split filters and digital decoding logic to convert incoming telephone dial tones into standard 4-bit binary logic signals. Equipped with a 3.5mm audio jack, it can directly access DTMF tone signals from landline phones, mobile phone audio output and signal generators. When the module detects valid dial tones, the status pin will trigger and the onboard LED indicators light up, helping you judge decoding results quickly. The decoded 4-bit data pins can connect directly to Arduino, STM32, Raspberry Pi and other MCUs without extra analog decoding circuits. It supports all 16 standard DTMF characters including digits 09, *, # and A, B, C, D. This module is widely used for telephone remote relay control, phone access control systems, audio signal identification, wireless remote trigger and interactive maker experiments. Please note this module only decodes DTMF dial tones and cannot realize voice speech recognition. Verify your audio signal level before wiring to avoid unstable identification.

Specifications

Brand: AJMRTC

Chip Model: MT8870

Decoding Type: Standard DTMF Tone (0-9, *, #, A, B, C, D)

Audio Input: 3.5mm Audio Jack

Output Interface: 4-Bit Binary Parallel Output + Status Pin

Working Voltage: DC 5V

Working Current: About 10mA

Operating Temperature: -40°C ~ +85°C

Application: Telephone Remote Control, Access Control, Arduino DIY Projects