Just had imon installed this past weekend. The technician said they have a list of modems that are approved that must be used. I still can't seem to find a consistent list as there are two webpages with different lists of modems - one that OP listed above, and this one. When I called imon to sign up for service, the sales guy faxed me a different list as well.

As mentioned already, the modems on all the lists are quite older and hard to find for new online. I ordered a new DPC3000 from Amazon for $50 and the technician installed it without any hiccups.

Still, even the $50 modem will pay for itself after 8 months. Definitely worth having your own modem