Do you mean the USB A-B cable? I've never heard it called that - though I guess that's the most common use. I have two - both on scanners. If somebody mentioned printer cable I'd think of an old Centronix cable whch were used with printers for years.

We still don't know if this monitor has USB - and if so why.

Mr Red wrote: Laptop PCs used [DisplayPort] before deciding on the far more ubiquitous HDMI

DisplayPort is superior to HDMI - you can attach more than one monitor to it for a start. I think you'll tend to find it on business laptops, like the aforementioned Lenovo T410S. HDMI ports are perhaps found mainly on cheaper laptops, or ones used for entertainment.

Interesting that Guest couldn't find a way to use it for audio. As he said, it should be possible, but if nobody does it there will be a lack of driver support.