Finally a bit of progress this afternoon! I was checking the termination of cable shields and all was normal as per install specs.

But yet again I removed the SL30 from its tray but this time when reinstalled in the tray, presto magic!, the MX20 was receiving data!

So I've now narrowed my focus to the SL30 serial Tx and Gnd pins. Anyhow, all is working at the moment so I think I'll leave well enough alone!

This stuff can drive one nuts!

Angier Ames

N4ZQ

Good data on all four MX20 ports.