Several times we needs a simple RS232 interface, between TTL and RS-232 logical levels. For example, various equipments have TTL output (0 - 5 Volts), which it's not compatible with COM port on PCs, Laptops etc, that needs " + / - " Voltage Level.
MAX 232 is an excellent IC, that works very well, just by using five capacitors.
FIG.1 shows the electronic diagram. The IC including 4 inputs and 4 outputs.
Figure below shows the PCB and Components Layout.
All capacitors are Tantalium-type. Table on Fig.1 describes the Capacitors values depending upon IC type, but I have used the MAX232 with 1uF cap's. You can easily find it.
Fig.3 shows the MAX232 construction on PCB (Left) with 7805 regulator in the same PCB. Picture on the Right shows my PCB.
Makis SV1BSX(Febr.' 03)