MT8870 DTMF Audio/Speech Decoding Telephone Module
Review: 5 - "A masterpiece of literature" by John Doe, written onMay 4, 20020

MT8870 DTMF Audio/Speech Decoding Telephone Module

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  • Product SKU: KG245
₹ 135.45 ₹ 208.95
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This DTMF Audio/Speech Decoding Telephone Module component is ideally suited to adding dual-tone multi-frequency (DTMF) decoding to your project. This detection module interprets the incoming tone and produces a coded output that can be connected to all manner of microcontrollers.

DTMF Telephone Audio Speech Decoding Module is commonly found in touch-tone devices such as a phone. The tone is a combination of two separate sine waves that produce a unique signal that can be transmitted or heard. When the module receives the signal it is able to decode it and produce a binary output that can be used in other devices. The module shows the state of the signal through onboard LEDs.

As an idea, you can connect up a mobile phone via 3.5mm to 3.5mm cable to the module. Dialing into the phone from a second mobile and then using the keypad will produce the tones on the original phone. The Voice Tone Decoder Module in the call can then be interpreted by the module, allowing you to control all manner of projects. The pins are suited to standard sockets with a pin pitch of 2.54mm.

The MT8870 Tone Decoder is a kind of commonly used multi-frequency decode IC product developed by the MITEL company. It is a complete DTMF receiver. After it received the DTMF signal, it will divide the signal into high-frequency group and low-frequency group and send the signal to the digital decoder which can figure out the key-value then send it to the outside Bus via four lines( Q1, Q2, Q3, Q4) as the binary form.



  • 100 Percent brand new and high quality
  • Onboard voice input interface
  • Low power consumption
  • Internal gain setting amplifier
  • Onboard LED, it is very convenient to check the output state.


    Technical Details

    • Main Chip: MT8870DS
    • Working voltage: 5V
    • Power Consumption : 500mW (MAX)
    • Type : MT 8870 DTMF Tone Decoding Module
    • Operating Temperature : -40-+85 °C
    • Board Colour : Blue

    Physical Attributes

    • Length × Width × Height(mm) : 27 x 25 x 10
    • Weight (gm) : 5

    Integration with Arduino

    Sample Code


    • Wired Robot control via mobile phone keypad.
    • Home Automation
    • Security Systems

    Additional Details

    • Adjustable guard time
    •  Central office quality
    • Onboard 3.5mm input interface
    • 5 Channel interface
    • On-board MT8870 frequency decoder chip
    • Power-down mode
    • Inhibit mode
    • Onboard audio input interface
    • Onboard LED lights for output state indicationComplete DTMF Receiver.
    • Does not require external circuits or wiring, it can be inserted directly into the UNO/MEGA2560/DUE board to use.
    • 12-Digital outputs decode mobile and fixed telephone keys (0-9, * #). Also, another 4 Digital output(ABCD) can use “DTMF Dial” for Software control.

    Product Video


    Package Includes

    • 1 x MT8870 DTMF Audio/Speech Decoding Telephone Module

    Customer Reviews

    Based on 11 reviews
    Works as expected!

    Hooked one of these up to an Arduino (followed a random tutorial, they all seem to be exactly the same out there) and it just worked--detected the tones every time.

    birender sharma
    It worked very nicely right out of the package

    This was exactly what I needed in my arduino project! It worked very nicely right out of the package.

    suresh kumar
    These work great.

    Using these for a special telemetry project for a client and they work very well.

    Worked great. Sturdy construction.

    They worked great! Used with an Adruino to grab dtmf reporting tones from an alarm system dialer. Tones are extremely short/fast. Worked like a charm.

    Michael Hite
    Five Stars

    Work as advertised.

    amit kumar
    Used with Baofeng radio

    These little DTMF boards are awesome. I connect the IN pin to the tip of a 2.5mm speaker jack connected to a Baofeng radio to control 4 relays using the radio’s keypad to send dual tone multi frequency tones.

    rajeev sharma
    A Great Value for a DTMF Decoder

    I bought the two pack of MT8870 decoders. They arrived quickly and worked flawlessly. They are so small that they are difficult to secure in place, but I'd certainly buy them again.

    bobi khan

    Works well

    md hasan @ sahil
    Nice simple hardware dtmf decoder. Much more accurate than software based decoding

    Worked perfectly. Very easy to program for using Python. Much more accurate than software based decoding. Im using this with svxlink.

    jai prakash
    perfect, 5 stars

    Both work like they are suppose to, at a great price.