Is the SB6183 Compatible with Centurylink?

no. the SB1683 is a cable modem only. 

Not compatible with centurylink’s dsl/fibre offerings. 

Thank you, plemans. I thought so. What inexpensive modem do you suggest? Tks.

I’d suggest the one centurylink makes you get. 

You should be able to check with them but they’re not good at supporting 3rd party devices. 

If you have fibre, you might just be able to get an ONT from them to direct connect a router to. 

But they might require a gateway for that in your area. Or if you have DSL, they have certain requirements on gateways. Your best bet is to check with them.