MT8870 DTMF Audio/Speech Decoding Telephone Module



  1. Onboard voice input interface
  2. Low power consumption
  3. Internal gain setting amplifier
  4. Onboard LED, it is very convenient to check the output state.
  5. Adjustable guard time
  6.  Central office quality
  7. Onboard 3.5mm input interface
  8. 5 Channel interface
  9. On-board MT8870 frequency decoder chip
  10. Power-down mode
  11. Inhibit mode
  12. Onboard audio input interface
  13. Onboard LED lights for output state indication Complete DTMF Receiver.
  14. Does not require external circuits or wiring, it can be inserted directly into the UNO/MEGA2560/DUE board to use.
  15. 12-Digital outputs decode mobile and fixed telephone keys (0-9, * #). Also, another 4 Digital output(ABCD) can use “DTMF Dial” for Software control.

2 in stock (can be backordered)

SKU: OLAM0018 Category:


Audio/Speech Decoding Module

This Audio/Speech Decoding 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 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 Audio/Speech Decoding Module shows the state of the signal through onboard LEDs.

The MT8870 module is a low power device DTMF decoder chip. It is a complete DTMF receiver integrating both the band-split filter and digital decoding functions. This Audio/Speech Decoding Module is suitable for modem interfaces, mobile radios and other DTMF related applications.

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 tones 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.