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MT8870- A Comprehensive Guide

Control of robots is easy with the MT8870 DTMF (Dual Tone Multi-Frequency) decoder module. How does the Module operate? 

Check out our guide for comprehensive insights on its pinout, features, and application.

What is the MT8870?


Mobile Phone Keypad

Mobile Phone Keypad


It is a DTMF module sound in remote control of robots via a mobile phone keypad or telephone voice dialing. Also, it is significant in home automation projects that involve a mobile dial pad input. 

Primarily, the Module is a tone decoder with a 3.5 mm audio connector socket. It is the terminal where an input audio signal enters the Module. 

MT8870 Pin Configuration

The Module can have 18 or 20 pins. The table below gives the pin configuration for both types.

Pin Configuration Table

Pin Configuration Table Pin Configuration Table

Pin Configuration Table


The Features of MT8870

How to test MT8870 output?


It is essential to try the Module before interfacing it with a microcontroller. Here are the critical steps in this process. 

  1. Connect the mobile phone's audio jack to the MT8870 DMTF Receiver input. 
  2. Next, press the dial tone key( any). It's essential to confirm if the keypad tone setting is in muted mode. If it is, turn it on. 
  3. Lastly, check if the LEDs are responsive, as shown below in the tone decoding table.


Tone Decoding Table



Pin Configuration Table

The Module is functional on PCs.





The module discussed above is one of the most critical components in robot control and voice dialing applications. If there's more that you'd like us to clarify, reach out to us.