Thanks to a late-night EBay binge last week, I became the proud owner of a UE-RA15SC-A USB/RS232 converter this morning. Fifteen bucks, how can I go wrong ? It's ten feet long and has a electronics bump halfway along that's the size of my thumb.
It took me a half hour of Google searching to find out the OEM is a Chinese company called WanTeng; they really like to paste "OEM" all over their stuff, and the documentation is lousy. Fortunately it's based on one of the popular FTDI USB chipsets, so they know more about it than the OEM does.
It wouldn't install correctly... Windows wanted to use the "USB.INF" driver instead of the one that came with it. That led to a "a function driver was not specified for this device instance" error message.
This may be my fault; this PC has had three USB/RS232 converters connected to it in the past, and I have been abusing it's registry and PNP setup to try to get a PCMCIA serial port working.
I uninstalled the drivers for all of the add-on serial devices I had, then rebooted... and PNP worked correctly. I have a COM3 !
I was pleasantly surprised to find that it correctly did DF1 Autoconfig to an SLC-5/05 serial port in Windows 2000 SP2; none of the other converters I've tried did that.
[later edit]
Now that I've gone back to it, I find it keeps getting re-detected as new hardware... I'm going to have to figure this out.