MT8870 DTMF Module

This DMTF module, based on the MT8870 chip, can decode telephone tones. These are the tones you hear when entering a phone number.
On the 3.5mm connection you can eg connect your mobile phone that can transfer these tones to the DMTF module.
This allows you to use your mobile eg as a keypad (to enter a code or number sequence)

Specifications:

• Voltage: 5V DC
• 3.5mm jack connection
• Can distinguish 16 different telephone tones (via Q1, Q2, Q3 and Q4 pins)

To get started with Arduino one can look here: MT8870 DTMF Decoder Module - Arduino Test with PWM Audio Synth Tones

For more information about the chip, look here: MT8870 Datasheet