DTMF Decoder Module based on MT8870

The DTMF Decoder Module based on MT8870 (Dual Tone Multi-Frequency) is commonly used to control robots with a mobile phone, it is also used in different kinds of home automation projects where mobile dial pad input is required. This module works as a tone decoder that uses its 3.5 mm audio connector socket to get the input audio signal. It is popularly used for mobile and fixed telephone voice dialing and recording related functions.

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.

Features:

• Onboard 3.5mm jack input Facility
• MT8870 Based Frequency Decoder
• 5 Channel Interface
• Detects 0-9, A-D, *, #
• LED notifier for Output state
• Low power consumption
• Internal gain setting amplifier
• Onboard LED, it is very convenient to check the output state.
• Adjustable guard time
• Central office quality
• Power-down mode
• Inhibit mode
• Onboard audio input interface
• Onboard LED lights for output state indication Complete DTMF Receiver.
• Does not require external circuits or wiring, it can be inserted directly into the UNO/MEGA2560/DUE board to use.

Specifications:

• 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
• Dimension (LxWxH)mm: 37 x 25 x 12
• Weight: 5g

Pinout Description:

Pin Name    Function                               Comments

Q1               Binary Bit 1

Q2               Binary Bit 2

Q3               Binary Bit 3

Q4               Binary Bit 4

STQ            Delayed String Output            Represents Binary Bit 0

STQ            Power Down Input

IN                Inhibit Input                            Logic high inhibits the detection of tones representing characters A, B, C and D

VCC            DC Supply Input

Package Includes:

• DTMF Decoder Module based on MT8870