Timothy Gray asked:
>Which is better to use  the MAX232 chip or a set of 1488/1489 serial line
>drivers?  I'm looking for stability and protection for the pic circut. I've
>noticed that most commercial products still use the 1488/1489 pair instead of
>max232's. is there a reason besides cheap??

If you're going to use 1488/1489, you will have to have +/- 12 Volts
available on the board.  The advantage of using these chips is not only that
they're cheaper than MAX232s, but they use up less real estate on the final
product (more drivers/receivers per chip and no need for 5x external caps
per chip).

If this is a one off, go to the Maxim site and pick the part that has
exactly the features you want (ie internal caps, 5 output 5 input, etc.) and
get them to send you a few samples.

I've never had reliability problems (ie ESD) with Maxim parts, but I could
be lucky.

For all of my latest projects; I short DTR/DSR and CSR/RTS on the board and
use a Dallas Semiconductor DS275 (which "steals" negative voltage from the
device you're communicating to) and essentially create a three-wire RS-232
interface.  This is the simplest, smallest, cheapest and lowest power
solution that I've found.  I haven't had any problems with it up to 19,200
bps.

myke

Twenty nine years ago this week, Neil Armstrong walked on the moon for the
first time, this week in myke's Book Room,

http://www.myke.com/Book_Room