AndrŽ Malafaya Baptista wrote:
> <snipped>
> This IC you refer, does it exist at the output of the serial port? Or should
> I put one there?
> 
> Thanks,
> AndrŽ

  The 1488 and 1489 "always" exist on any standard serial port (And on
the better ones, they're socketed so if you should burn them out, you
can replace them, IMHO at least.)  Some LSI circuits may include them
internal (on the FGPA etc.), but not always.

  The really good thing about those is, they don't usually burn out
unless you do something really nasty abusive to them {like wire 117VAC
to a serial port, or strike it with lightning}, they're reasonably tough
IC's, billions produced, & I haven't replaced many that I can remember. 
And even Radio Shack carries spares, should you ever need more <G>  (Way
overpriced tho.)

  Mark, mwillis@nwlink.com