Do you have DDUtil running to direct the CAT commands? (Some folk mention using other programs like OmniRig, but I've not done so personally.) It appears that RDXcluster might look to a middle program to transport the CAT commands. Documentation is pretty sparse....
Here is a RDXclunster link http://www.mdxc.org/swl/art-rdxcluster.php
DDUtil at http://k5fr.com/ddutilwiki/index.php?title=Main_Page
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