Comcast STANDARD cable, What type of boxes do they use?

I don't know if anybody is going to be to help, but I'm basically
curious what type of cable boxes are compatible with Comcast's
standard cable service. I called Comcast at the 1-800-COMCAST number
and they basically jerked me around for fear that I might be trying to
avoid having to rent a cable box directly from them. The last time I
checked owning your own cable equipment wasn't illeagal, but it
certainly doesn't look like Comcast is going to assist me in the hunt
for a box. If anybody could help it'd be much appreciated.