On Wed, 2002-05-15 at 20:54, [EMAIL PROTECTED] wrote: > FWIW - On one industrial site I measured 70VAC between the earths of two > buildings, but since we were using isolated differential signalling (20mA > loop) and the opto-isolators were rated at 2.5kV isolation we didn't have > any networking problems.
What exactly is an opto-isolator? Is it the same as an opto-coupler? I'm guessing that its a smallish box with two ports ( a two-port switch if you prefer ) that has a sending light and a receiver pair twice (one pair for TX/RX and RX/TX) so that the two sides are not electrically connected. What is one worth? Do they need power? How much are they? Who makes them?
