Making an RS-232 to TTL Adaptor

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RS-232 adaptor parts

The RS-232 standard for serial communication was defined many years ago, before computers were commonplace. It specifies the signal levels for communication between a Teletype machine and a modem, with relatively slow baud rates and cables no longer than 50 feet. The signals were defined to switch between +12 Volts and -12 Volts, with clearly specified tolerances. When working with 5V logic, this requirement is inconvenient and has led to a range of chips that make the conversion, or "level shifting" somewhat easier.

Parts List
QtyItemFarnellRS
19-pin male D-connector  
14-pin Molex KK connector  
1MAX232A  
50.1μF ceramic capacitor  
1Red LED, 3mm  
1Resistor  
1Tri-pad board (Maplin's)  
19-pin D-connector shell (red)469-890 
19-pin D-connector shell (blue)469-907 

To Be Continued....


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