I learn not to assume anything about technical material . I have search Amazon for a specific Cisco modem , and this one come up . it be a Cisco CM-100 , which accord to Comcast 's list of recommend modem be not a recommend model . I could not determine what model it be until I open the package and soon learn that I would get to pay return postage . if it do not list a model number , there likely be a reason , and I presume that in this case , the reason be that it be not on Comcast 's list !