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?

Thanks in advance (TIA)

Sincerely,
Randy Walsh