Third party serial cable, VCDS Lite tests OK, but won't read anything

Serial cable and USB to serial adapter combo, both of unknown origin.
A kind forum member gave me this cable and adapter around 2006 when I got my 1996 Passat and I played with it some on my laptop of XP vintage, which upon checking specs now, confirms it had a serial port, so I probably didn't try to use the USB adapter.
Fast forward to now. My son is driving a 2001 Golf and due for timing belt. Been a long time since I did the Passat and Golf is newer engine not quite the same, so read up the articles, watched YouTube videos, went back to Bora Parts for the parts, Metal Nerd for the couple other tools not in the set for Passat. All set to dive in this weekend, but need to get VagCom going to check timing.
So I plug in USB adapter, find the driver with device ID (HP win 7 laptop), download VCDS-Lite 1.2, plug up to car, select the comm port shown by the adapter in the device driver. It tests OK, reporting excellent latency etc, identifies cable as non RossTech with optoisolation or something like that.
But it is unable to open any controller. Pushed all the buttons, scanned everything that can be scanned and it fails to come up with anything.
Is there anything I've missed in setup? I've spent enough already on parts and tools and I don't really want to spend a lot more on a "real" cable that will mostly just sit on the shelf.
Was hoping to do the job this weekend, but don't want to start it if I can't finish it, which is the timing check/adjust.
Hard to know if it's the USB adapter - it apparently worked for the previous owner - or something else.
Thanks in advance for any attempts to help!
I also have a Scan Gauge and it hooked up just fine and read and cleared the codes (the Check Engine has been on).

Update:
Found another USB/serial adapter in my misc IT junk at work today and this did the trick! This one is a TrendNet brand, though seems to use same driver as the other one. So VCDS now can read data. Didn't realize I still need to spend $99 to activate the software to enable the timing check, but at least I now have a path forward.

Before you purchase a VCDS-Lite license for $99, please keep the following in mind:

• VCDS-Lite is locked down to the computer it is registered to. We allow one and only one transfer to another computer.
• VCDS-Lite is for serial port interfaces, it does not support any sort of USB. The use of USB adapter is not supported by Ross-Tech, please see our FAQ 3.3.
• 3rd party interfaces have a spotty track record, a quick search here and you will find a lot of postings over the years about this. Please be sure EVERY module in your car can be scanned BEFORE paying for the full version of VCDS-Lite. For example, the ECM may talk just fine, but your set up may not talk to the ABS or CCM.
• We have a kit starting at $199, this gets you our HEX-V2 (3 VINs) interface and the full version of the VCDS software. It works with 1995 to current models. You would not be locked down to a single computer like VCDS-Lite is and you would be getting a true USB device.
• We have a LOT of customers with VCDS-Lite, it is all they need and is a good fit. And we get a steady drum beat of registered VCDS-Lite customers who's set up is falling short and they end up upgrading to one of our current HEX generation kits for an additional fee.

I can blah blah blah here for a while, but the best sales pitch I can give is to let our customers chime in with their opinions on their Ross-Tech investment.

Regards.

I purchased my VCDS around 10 years ago, and could not be happier about my decision. In all that time I have only read 3 or 4 TDI's, but for all the goofy things that happen over time having the full version has been indispensable. VCDS was truly money well spent.

jef@rosstech said:

Before you purchase a VCDS-Lite license for $99, please keep the following in mind:

• 3rd party interfaces have a spotty track record, a quick search here and you will find a lot of postings over the years about this. Please be sure EVERY module in your car can be scanned BEFORE paying for the full version of VCDS-Lite. For example, the ECM may talk just fine, but your set up may not talk to the ABS or CCM.

Click to expand...

Thanks for the caveats and advice here. I just tested again and verified it can read a lot of modules. It's not clear what modules exist in my 2001 Golf, but clicking buttons for ones that probably exist are all coming up.
So I've gone ahead and placed the order to register VCDS-Lite. The timing-belt (and water pump) job went OK this weekend and test drive seemed good. So now just need to check/fine tune the timing.
For anybody wanting to know the USB-serial adapter, it is a TrendNet TU-S9. Windows 7 was able to find and download a driver "automagically" and install it at COM4. VCDS-Lite test said latency was excellent.

Our wiki page has the list of what modules are found in the mk4 Golf platform:

http://wiki.ross-tech.com/wiki/index.php/VW_Golf/Jetta/Bora_(1J/9M)

A common issue people get mixed up on:
Manual Crank windows = 35 - Central Locking
Power Windows = 46 - Central Convenience








C?ID=365855&TC=1