My company sells a Windows-based industrial alarm notification application, and one of the alarm announcement options is to use a USB Voice Modem to a standard phone line. Several of our customers have started having problems getting the numbered COM port (COM3: etc.) to show up in the Windows Device Manager when running various Windows platforms under ESXi 6.7 and 7.0.
One customer in particular has become quite accusatory that this failure to detect the modem is somehow the fault of our app. I've tried to explain that our app would work if Windows could see the modem as a numbered serial port. He seems to think I'm attempting to deflect the blame.
I found the following article: https://kb.vmware.com/s/article/2147650
It looked very promising, and I suggested that he give the solution outlined in that article a try; however, he is (exasperatingly) unwilling to take my suggestion unless I can give him some sort of authoritative assurance that it will work... Unfortunately, I do not have ESXi installed on my development machines, so I can't replicate his precise setup; my coworkers up in the main office have been unable to get ESXi installed on one of their test machines (and I'm unable to help them because I work from home, 400 miles away).
The customer is getting impatient, so I thought I'd float my question here to see if anyone here can give an endorsement authoritative enough to convince my customer that disabling vmkusb (as outlined in the knowledge base article) would be a reasonable thing to try to fix the missing modem COM port problem.
The modem we are using is a StarTech USB dongle modem (which uses the Conexant CX93xxx chipset):
When I install the modem under normal (non-virtualized) Windows, everything works fine.
When the customer runs it under ESXi 6.7 or 7.0, no serial port is available for our app to open.
Note: The USB Voice Modem is a Composite USB Device which defines two interfaces in the Windows Device Manager:
mdmgl006.inf - Supports Windows TAPI
usbser.inf - Supports numbered serial port (e.g. COM4:)
Does vmkusb have a known problems with composite USB devices (such as this type of modem) ?
Is the procedure outlined in https://kb.vmware.com/s/article/2147650 a viable solution?
Thanks