At 12:19 PM 10/03/97 -0800, you wrote:
>Need help with a little hardware RS232 inteface.
>
>Description: I've created a PC stepper motor interface using a 16c84 and a
>2003.  I'm currently doing Serial I/O straight from the 16c84 to the PC
>
>Question: If I use 1 of then 2003 drivers to boost the TX line (from pic to
>PC) to +12 volts, would this damage the PC?  (I thing that the RS232 spec
>is only +10 volts), what must I do to safely drop the voltage to 10 volts?

1.      Pair of diodes,
2.      Resistors
3.      2v7 zeners

And remember you will have some (minor) saturation of the output transistors
in the 2003 anyway.

Most PCs can quite comfortably handle 12v - but of course you should not rely
on continued use at the maximum.

Though shouldn't you have a -ve voltage on the TX line when off - say -3v, this
will help in noise rejection in case  your line floats above 0v when not being
driven !

Rgds

Mike

Politicians, like babies nappies should be changed often - and for the same
reason.