before I purchase this modem , I do some research . I be not techy and be worry about buy something I could not use with Comcast , my internet provider . I call Comcast and they tell I this particular Motorola model -lrb- any model over `` 5000 '' -- related , apparently , to model number -rrb- would work . I look at post on techy site . some user have report trouble with activate they modem with Comcast . I , fortunately , do not run into trouble . I connect the modem -lrb- it be very easy -rrb- . I call Comcast . I provide they with the serial number -- and the `` hfc MAC ID '' number . both of which be located on the box the MODEM come in . I be tell the `` MAC ID '' number be what Comcast principally use to activate the modem through they system . so far , so good . it be easy to set up and be work as expect . and I love not give extra money to Comcast because I no longer rent they modem and router .