<hardware> A kind of electrical connection using two wires,
one of which carries the normal signal (V) and the other
carries an inverted version the signal (-V). A differential
amplifier at the receiver subtracts the inverted signal from
the normal signal to yield a signal proportional to V. This
subtraction is intended to cancel out any noise induced in the
wires, on the assmption that the same level of noise will have
been induced in both wires. Twisted pair wiring is often
used to try to ensure that this is the case.
The two wires might be connected at the receiver to separate
analogue to digital converters and the subtraction performed
digitally.
The RS-422 serial line standard specifies differential
drivers and receivers, whereas the earlier RS-232 standard
does not.
