As long as it is not a phone modem, yes he can purchase his own modem. He will have to call us to add it to his account, we'll need the brand and model number of the modem, and the modems MAC address. Stevensville, MD is an area that is docsis 3.0. Of course the customer has to pay for the speed if they want to upgrade to the 20mb or 40mb connection to take advantage of a docsis 3.0 modem.
Approved modem list. »www.atlanticbb.com/pdf/Approved% ··· List.pdf
I would recommend a motorola 6120/6121/6141 or Arris cm820a.