Upsampler and DAC not talking

Just received my Vivaldi stack (upsampler, DAC, clock) and am having trouble with the DAC not showing up in Mosaic or talking to the upsampler. dCS support is looking at this but I just thought I’d post here to see if anyone else has had and solved this problem. We have made sure the rs-232 protocol is binary, and even tried a different null modem cable all to no avail. Thankfully the unit plays via Roon fine but I can’t use Mosaic to try the different filters on the DAC or do anything on the DAC except via the front panel. Any ideas?

Thanks,
John

Have you checked the obvious i.e. that the correct connectors on the RS 232 cable are connected to their appropriate sockets on the components? BTW, what goes where is marked on the wires.

Yes I saw the labels and dCS support had me double check that first thing. Currently have a plain null modem cable from Amazon attached per dCS support but still no go.