I'm able to remote a HID device, but not a serial device

Hi! I've read through the client and linux faqs, but I'm still stuck. Using the script at https://github.com/virtualhere/script, I've installed the server on a Jetson Nano. I've then installed the client on a Mac running 10.13.6. If I plug/unplug devices on the Nano, I see them come and go on the client, so something is working. I can even plug a mouse and keyboard into the Nano and drive the Mac. Neat!

My problems is that I'm actually trying to remote what I believe is just a fancy serial adapter. It's a little thing to read CEC packets on an HDMI bus, made by PulseEight. When I plug that in to the Nano, I see it appear in the client. I say I'd like to use the device and it switches to : In use by you. However, when I run the tool that accompanies this device, it doesn't find the port.

I've also tried my Saleae logic analyzer (which again, I'm pretty sure is just a serial port) and it doesn't work either.

Do I need to do something extra to get serial devices to work? Is there a way to know which tty it's mapped the device to?

Thanks!