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MT8870 DTMF VOICE DECODING MODULE
₹85.00
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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:
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- 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:
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- 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:
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- 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)
- Input Side:
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:
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- 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
Equivalent Modules:
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- CM8870 Module: Pin-compatible alternative
- HT9170 Module: Alternative DTMF decoder IC
Resources:
Package Includes:
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- 1 x XD-61 DTMF MT8870 Voice Decoding Module
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