yo - replace my 7 year old Motorola 5051 Surfboard for this one on my Comcast Internet service . no instruction come with the modem - just power supply and a cat5 cable -lrb- which be strange - because cat5 be a 10\/100 cable and the modem be 10\/100\/1000 -rrb- so the cable be useless . install modem power up both modem and computer - log onto the internet - Comcast recognize that there be a new sheriff in town -lrb- modem -rrb- ask for my account number - spend about 6-7 minute do something and then wallum - it be all set up and work great . I have run speedtest.net test before and after the change out and I be get 10-15 % faster up and download than before . happy = yes I be !