Name: MT8870 DTMF VOICE DECODING MODULE
Brand: Generic
SKU: IFT00024-1
Availability: InStock

MT8870 DTMF Decoding Module is a complete dual-tone multi-frequency (DTMF) receiver module that converts telephone keypad tones (0-9, *,#, A-D) into 4-bit binary output. Based on the MT8870 IC, this module is ideal for telephone-based control systems, remote automation, and interactive voice response applications.

Key Features of MT8870 Module:

- Complete DTMF Receiver: Decodes all 16 DTMF tone pairs
- Digital Output: 4-bit binary (Q1-Q4) and 1-bit Strobe (STD) output
- Built-in Filter: Onboard bandsplit and decoder filters
- Simple Interface: Directly connects to microcontrollers
- Adjustable Sensitivity: Can be modified via external resistors

Technical Specifications:

- Operating Voltage: 5V DC (4.75-5.25V)
- Current Consumption: 10mA typical
- Frequency Tolerance: ±1.5% (meets telecom standards)
- Output Format: 4-bit binary (Q1-Q4) + Strobe (STD)
- Response Time: 40ms typical tone detection
- Input Impedance: 100kΩ (adjustable)
- Module Dimensions: 40mm x 30mm

Module Pinout and Connections:

- Input Side:
  - IN+: Positive audio input
  - IN-: Negative/ground audio input
  - VCC: 5V power supply
  - GND: Ground
- Output Side:
  - Q1-Q4: 4-bit binary output (LSB to MSB)
  - STD: Strobe output (goes high when valid tone detected)
  - OE: Output enable (active low, tie to GND if unused)

DTMF Decoding Table:

Key	Q4	Q3	Q2	Q1	Binary	Hex
1	0	0	0	1	0001	0x1
2	0	0	1	0	0010	0x2
3	0	0	1	1	0011	0x3
4	0	1	0	0	0100	0x4
5	0	1	0	1	0101	0x5
6	0	1	1	0	0110	0x6
7	0	1	1	1	0111	0x7
8	1	0	0	0	1000	0x8
9	1	0	0	1	1001	0x9
0	1	0	1	0	1010	0xA
*	1	0	1	1	1011	0xB
#	1	1	0	0	1100	0xC
A	1	1	0	1	1101	0xD
B	1	1	1	0	1110	0xE
C	1	1	1	1	1111	0xF
D	0	0	0	0	0000	0x0

Typical Applications:

- Telephone Remote Control: Control devices via phone keypad
- Interactive Voice Response: Telephone menu systems
- Security Systems: Remote arm/disarm via phone
- Home Automation: Phone-controlled appliances
- Electronic Locks: DTMF-based access control