[BBKing]

OK, Bill C has touched upon this in his elegant way.

Back in the last century, there were two cable companies. One (CWC), like the far-sighted lantern-jawed pioneers that they are, specified Cisco UBRs with EuroDOCSIS CMTS cards for their cable network, with EuroDOCSIS STBs hanging off them, all designed as a single system.

The other (ntl), low beetle-browed scurrying troglodytes that they were, specified DOCSIS to match the off-the-shelf available cable modems (there weren't really any ED modems back then, DOCSIS is the US protocol designed around the existing US TV channel structure and the first modems were all targeted at the US).

Anyway, what we are left with after the two companies merged is two systems, often in conjoining areas. One of the pre-requisites for the launch of standalone modems in former CWC areas was the availability of a EuroDOCSIS (dual protocol actually) SACM. However, the existing DOCSIS only stock of modems has to be kept off the ED network to avoid annoying technical problems (like the modem not working, in other words).

In the North-East the Wearside area (aka Sunderland) is EuroDOCSIS ex-CWC while Middlesbrough, Hartlepool, Stockton are all DOCSIS original ntl areas. Hence a DOCSIS only modem from the latter areas will NOT work in the Sunderland, come rain, shine or promotion to the Premiership.

In the case of the OP's client in Sunderland, I'd strongly recommend changing to Ethernet, which is nature's way of connecting to broadband. Leave USB for digital cameras and other trinkets. I've not known of any cases of Ethernet crashing a computer in the way USB can.