DTMF PPT Slides

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Title Slide

Basic Premise

Follow-on Ideas

Dual Tone Concept

Dual Tone Frequencies

Freq to Binary Code Chart

Tone Encoder

Encoder Box

Arduino Gets 4-bit Input

Arduino 4-bit Out Converted to 16 Channels

Tone Decode Board

MT8870 Decoder

Frequency Separation Chart

Triac Board

TRIACs

Latching Circuit

J-K Flip-flop as Latch

Latching System

Software Considerations

Arduino Sketch

Setup Function

Loop Function

Access Code

Code Continues

Code Continues - Access Code

Code Continues - Status Check

Code Continues - Mode B

Code Continues - Switch Selection

Code Continues - Activate

Code Continues - Activate

Code Continues - Activate

Code Continues - Deactivate

Code Continues - Deactivate

GetDTMF() Function

Example of Serial Interface Screen

Serial Interface Screen Con tined

Keys 9 and 0 reached

Phone Line Connection

Data Access Arrangement (DAA)

Arduino Interprets the Phone Line

Project DAA Circuit Board

DAA Schematic

Phone Hook-up Block Diagram

How to Use the System

Summing it Up


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