> 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?

RS232 specifies that each line must be in 1 of 2 states.  One
state is a voltage between +6 and +25 at the transmitter output
pin (after losses, +3 to +25 volts at the receiver input pin).
The other state is a voltage between -6 and -25 at the transmitter
(-3 to -25 volts at the receiver).

The range from -3 to +3 is not a valid signal level.  It's there
to provide hysteresis and a noise margin.  Lots of people use 0
volts as the low level.  But don't kid yourself that it's compliant
RS232 or that it will work with all devices.
                                                Lee Jones

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