Quite often the COM port with USB/serial converters is not COM1 to COM4. IIRC, this was a limit in some of the Meridian config applications although I believe this is now fixed with some versions so you can specify a com port outside this range - it was actually a windows API limit and an application kludge was needed to get it to recognise values out of this range (or was it >com8?). The other alternative is to specify the com port in the windows device manager for the USB/Serial device as 1..4 if slots in that range are free.

Meridian owner since 1992
Prime & PSU, Focal Elear headphones, Roon (ROCK 8Gi5 NUC), Explorer 1 & 2, F80. 200/203, various Sonos (via Roon).