MT8870 DTMF Decoder Module is a very tiny module that is based on MT8870 DTMF decoder ic. The module offers a 3.5mm audio connector to connect an audio source. The DTMF Signal in the audio source is decoded and the digital outputs on the module, indicate the key pressed. You may connect a phone to the module and the module will output the key(0-9, *, #, A, B, C or D)pressed on the audio source. This module is suitable for modem interfaces, mobile radios and other DTMF related applications. Can be used to build mobile controlled robots, home automation projects, IVR style applications, etc 
 
Specifications & Features of MT8870 DTMF Decoder Module:-
Working voltage: 5V
Power Consumption: 500MW(MAX)r: 500 mw (MAX)
On-board voice input interface
On-board LED, it is very convenient to check the output state.
 
Onboard 5 x LED indicators for easy viewing output state
Operating Temperature : -40-+85 °C
IO Drive : Current Maximum 10mA.
PCB Size : 25.4x25.4MM
This decoding module is for mobile and fixed telephone voice dialing decoding function
Designed specifically for ARDUINO Board. Can also be used for other MCUs(AVR PIC MSP430 STM32 ARM7/9/10/11 FPGA/CPLD)
Low power consumption
Internal gain setting amplifier
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
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.