My book, Electronic Circuits and Secrets of an Old-Fashioned Spy, explains in detail how to build the DTMF (TouchTone) Decoder shown to the right. Some understanding of basic electronics is recommended, but the strong-willed and stubborn can learn as they go along. If you'd like complete plans, including schematic, PCB layout and stuffing diagram, you can order the book HERE .

For those who already have the book or have read my article in Popular Electronics, below are the support items I promised.
 

Programs & Code
BS1 Program Listing
 

Foil Patterns
The foil patterns are provided here in Word Perfect Draw 6.0 format. By having direct access to the design, you can:

• Add something to the circuit
• Customize the board to fit parts from your own inventory
• Obtain a better printout of the pattern
• Laser-print directly to a transparency

The following patterns have been included:
Decoder Module
Binary Readout Module
7-Segment Readout Module
Combo Board for full LCD Version[combobrd.wpd - MISSING]

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