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See also (locked) thread:Only getting max download of 33 Mbps with new DOCSIS 3 Motorola SB6183 16channel modem and Premier upgrade
It took over a week to get to the right folks in support, but eventually the above forum post, mentioned to the @CoxHelp person I was Twitter DM'ing, made all the difference.
Hoping this forum post can help avoid some early adopter pains for other Cox customers who bought a SB6183. Let's hope they add the self-install menu option for this modem soon, so that proper provisioning would be painless.
In their defense, the self install worked for me. It didn't list the modem, but it did pop up with the serial and upon selection brought up the proper modem.In my research, I referenced your site not knowing that your problem had already been corrected.I still wish I was getting more than 8 channels, but I'm sure that will change sooner or later. :)