wrote in message
...

I bought 2 of these directly from RMS for $5 each a couple
of years ago. They work very well. I had a hard time finding
ANY "galvanic isolators".

http://www.rmscommunications.net/pdf/MI2120VPG69&70.pdf

The MCM is spec'd at a 2.4GHz bandwidth, so it might provide better
performance in some systems. (I have no idea what the upper limits of cable
systems are.)