DTMF Decoder

Module based on the MT8870 chip that decodes DTMF tones coming from a landline phone, a mobile and so on
DTMF Decoder - Image 1
DTMF Decoder - Image 3
DTMF Decoder - Image 4

SKU 8300-YC047EAN 8219671105477Item type: Assembled

Description

Module based on the MT8870 chip that decodes DTMF tones coming from a landline phone, a mobile and so on. The digital outputs can be wired to a computer, to Arduino or to any other microcontroller to build devices such as DTMF relay keys, alarm triggers, RC servo control and the like. It has 5 status LEDs, a 3.5 mm jack socket for the tone input and a 9-way pin strip for the power supply and the MT8870 pins. Power supply: 5 VDC, size (mm): 27x25x12.
Table
The table below shows the logic state of the 4 outputs of the MT8870 chip for each DTMF tone received. It also covers the tones for A, B, C and D, which are not normally found on the keypad of a traditional telephone.
Number STD Q4 Q3 Q2 Q1
no tone L Z Z Z Z
1 H 1 0 0 1
2 H 0 0 1 0
3 H 0 0 1 1
4 H 0 1 0 0
5 H 0 1 0 1
6 H 0 1 1 0
7 H 0 1 1 1
8 H 1 0 0 0
9 H 1 0 0 1
0 H 1 0 1 0
* H 1 0 1 1
# H 1 1 0 0
A H 1 1 0 1
B H 1 1 1 0
C H 1 1 1 1
D H 0 0 0 0
Documentation and useful links

 

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