My Arris TM 722G modem (that I own) was starting to fail so I went to the Comcast office and all they had for D3 EMTAs was their gateways. I do not want a gateway as I use an Apple AirPort Extreme router (which is like comparing a Ford Pinto to a Chevy Corvette) so they only had the older EMTAs in stock (D2) so they gave me a brand new Arris CM820A modem and an Arris TM602G EMTA so I rewired the phone system so it enters the wiring in the basement as opposed to the bedroom and installed a two-way splitter on the incoming wire with one leg going to the internet modem and the other leg going to the 4-way splitter going to the phone modem and three TVs. I also acquired a few tools from Lowe's and Home Depot to wire phones and cable wires and you can tell my fitting from the Comcast fittings. I also had a slight improvement in signal strength when I replaced a few jumpers as well. I use the Thomas & Betts Snap n Seal fittings (which are professional grade as they were used by Mediacom when I lived in Iowa).
I also made a few fittings that did not come out right so I just cut them off and redid them.
-- Romney-Ryan and Scott Brown are the Right Choice as they are Hope & Change you can count on.