CarBytes

[Andrew K. Mattei]

>one question, What is the difference betwee Andrew Mattei's and Carsten
>Meyer's?  I planned on building Carsten's design because its more simple.
>What do the four transisters in the circuit?


I'll field this one.

Carsten's design is dependent on the characteristics of the diode in the
circuit. Notice how he offers a couple of choices, and suggests testing for
which one works best. Since voltages in the RS232 port can vary slightly,
Carsten's cable may/may not work with different computers. (BTW, I know that
his circuit is far simpler and has fewer components, but I'm kinda partial
to the MAX232 circuits. ;) ). The four transistors used in the MAX232
circuit combine transmit and receive in to one bidirectional wire. There
needs to be four of them because if there were only two, the polarity would
be inverted. ;)

I'm in the process of building a bunch of MAX232 interfaces (most are going
to the F-body crowd to support Ken and Dave's LT1_Edit software), and with
the MAX232, it's pretty much a slam dunk that it will work with all the
differing RS232 ports. So, I'm eliminating the possibility of voltage
variances causing a cable not to work with a certain computer. :)

I've been using the MAX232 circuit (thanks :PPF!) for over two years now and
never had a problem with it. :)

-Andrew