MAX 232 is meant for 5 volt signal levels. Supply should be 5volts. But since 3232 is not available easily and are a bit too expensive for my project, I used 232 itself.

Now, my signals are 3.3 volts and not 5 volts. I have 2 options if I go against the datasheet.

1. Use 5 volts Vcc for MAX 232 and use 3.3 volts signals as inputs
2. Use 3.3 volts Vcc for MAX 232 and use 3.3 volts signals as inputs

Since the circuit inside MAX 232 is an analog charge pump, it works fine with both options. Only thing is that, RS 232 levels are in the range of +-6.5 to += 7.5 volts. But this, still drives another MAX or the chip in the PC.


My question was, what is better, option 1 or 2? option 1 gives me a higher output level, but I was wondering whether option 2 wouldn't give me a better level sensing... ie: in case the voltage goes to 2.9 volts....

It isn't good at all to go against the data sheets, but then in case of MAX232, it shouldn't be a big issue, considering what is inside - what do you suggest? I tried to fail the connection, but it seems to be working fine and this is tempting me !!