MT8870 DTMF Tone Decoder Module

The MT8870 DTMF Tone Decoder Module is an integrated audio decoding module designed to convert standard Dual-Tone Multi-Frequency (DTMF) acoustic signals (such as keypress tones from mobile phones or landlines) into 4-bit digital binary outputs. Built around the industry-standard MT8870 monolithic DTMF receiver IC, this module includes complete signal filtering, band-split filtering, and digital decoding circuitry on a single compact PCB.

Featuring a 3.5mm onboard audio input jack along with pin header inputs, the module receives dial-tone audio from mobile phones, telephone lines, or audio generators. When a valid DTMF tone is detected, the onboard STD (Delayed Steering) status LED lights up, and the corresponding 4-bit digital value (Q_1 to Q_4) is output to the header pins for direct processing.

This module is widely used in phone-controlled home automation systems, remote equipment switching, interactive voice response (IVR) hardware, and security control systems. It is fully compatible with 3.3V and 5V microcontroller platforms including Arduino, ESP32, Raspberry Pi, PIC, AVR, breadboards, and custom printed circuit boards (PCBs).

Specifications

Key Features

• Onboard 3.579545MHz crystal oscillator for precise tone decoding
• Low power consumption & high decoding accuracy
• Standard 2.54mm pitch header pins for breadboard and jumper wire compatibility
• Easy circuit assembly and modification
• Reusable / Durable design
• Compact and convenient for prototyping

Applications

• Mobile phone & landline controlled home automation systems
• Remote equipment & relay control via telephone lines
• Interactive Voice Response (IVR) & automated call switching systems
• Microcontroller (Arduino, ESP32, PIC) DTMF keypress processing
• Security alarm activation & remote door lock triggers
• DIY electronics & robotics projects
• Educational & lab experiments

FAQ

What is the operating voltage?
5V DC.

Which interface does it use?
3.5mm Audio Jack + 5-Pin Header Inputs.

Is it compatible with Arduino and ESP32?
Yes. It works with Arduino, ESP32, Raspberry Pi projects.

Can I buy the MT8870 DTMF Tone Decoder Module in Kanpur?
Yes – buy online with delivery across India, or pick it up from the iTechBuilders store, Damodar Nagar, Kanpur.