3.0
It is an EMTA so depending on the company, they may choose to not provision it.
Yeah. The ISP I work for always tells customers they must lease the EMTA from us if they have our phone service, but I know of at least one customer that owns his own and it works fine. Most of the CSRs would never figure out how to create the device in our system since the MTA part is done differently. If the user is going to use it only as a modem, they don't even need to mention that it's an EMTA. They should be able to simply provide the CMAC as the MAC ID and tell the ISP that it's just a regular modem.
Was it Arris brand? That's what my employer uses for EMTAs. I don't think a non-Arris EMTA would work for phone service in our system, but there's a very good chance it would work as a modem for Internet service.
That said, I've encountered compatibility problems with some modems. I've seen some Zoom modems that didn't work (and many that do). Recently, a non-retail Netgear modem seemed to be incompatible, but it was actually working fine even though I couldn't see any device behind it pulling an IP address.