The only issue you
might run into is the
ring signal from the CM11A. I don't recall what DB9 pin it used but it was used to wake the PC in advance of sending it any powerline activity received by the CM11A. Logging of PLC activity, triggering some macros, etc. occurs at the PC level. Different USB-Serial adapters handle handshake lines differently so without knowing which adapter, which NUK and which DB9 pin I can't offer any definitive advice.
If your NUK sleeps, it may need the ring signal, but how it handles it may differ from what was common in the days of the CM11A. And, if needed, how or if the ring signal traverses your USB-Serial adapter may be a problem.
As best I recall, Wake-On-Ring, when available, was set in the BIOS. I have a couple of Lenovo Q190 PCs which are a bit bigger than a NUK and which do sleep - I have to move the mouse or hit a key to wake them. Both run Windows 10 and I'm not sure how to access any BIOS settings that may be available were I to try interfacing a CM11A.
FYI:
https://en.wikipedia.org/wiki/Wake-on-ring This is the best source for USB-Serial adapters. They have excellent prices, excellent service and complete info on which signals are handled...
http://www.byterunner.com/byterunner/category=USB+to+Single+Serial+Adapters/exact_match=exact DUH!:
http://www.db9-pinout.com/It's been too long for my ancient gray cells. I had forgotten that the RI (ring indicator) was standard on DB9 connectors and always used pin 9.
I think one of Jeff Volp's units emulates a CM11A. So, he may be more current on this issue.