How to convert TTL to RS232

This small realization, based on one of the most common IC (MAX232) is designed to create a small and convenient TTL to RS232 and vice versa convertor.



All you need is 4 caps, one IC and 2 connectors. If you want to add a small regulator on the board (already foreseen on the PCB) you just need to add a 78L05 regulator and a cap.

If you do not need to regulate the power supply, you can just replace the 78L05 by a strap (pin1 to pin 3) and drop the 78L05, C1 and C2.

Schematic


PCB


Component Layout


Component List

C3-C4-C5-C6 : 10uF 16V

IC1 : MAX232

C1 : 100uF 25v (If regulated power supply needed)

IC2 : 78L05 (If regulated power supply needed)

C2 : 100nf (If regulated power supply needed)

DB9 Female

Connector

All Files and Prints

contributed by Olivier de Broqueville.