My recollection is that in addition, RS-232 specifies 12V, while RS-422
specifies 5V, although virtually all hardware will work with the lower
voltage.

DTL

--On Wed, Jan 5, 2000 4:28 PM -0800 Bill Studenmund <wrstuden@nas.nasa.gov>
wrote:

> RS422 isn't a protocol. It's a signaling standard. As a crude
> approximation, it's RS232 but with differential transmit and receive. i.e.
> a "1" is v+ > v-. RS232 is a "1" is a voltage between -3V and -12V (or was
> that -25?) relative to "ground". Yes, a "1" is a negative voltage. :-)