Answer 6

Why not? Hybrids work just as well at DC as they do for audio; you just need a receiver with balanced inputs, like an RS-422 buffer:

All resistors are the same value (e.g., 4700 ohms) and the transmit driver needs to be a voltage source (low impedance).

If the transmitter switches between, say, 0 V and 5 V, the opposite receiver will see a voltage differential of 0 V and 2.5 V, respectively, while the local receiver will just see 0 V.

For long lines, you'll probably want to use lower resistances and you'll want to limit the slew rate of the transmitter so that the receiver doesn't produce glitches on the transistions of the local transmitter.

If the RS-422 receiver is replaced with an opamp differential amplifier with a gain of 2, then any analog voltage transmitted by one end will be reproduced at the other end.

Contributor: Dave Tweed

Published March 2003