If you have Component Video I/F Record capability that works with HD Cable Box output resolution settings (not all will) you're good to go. But, if not...or you can't get it to work (if it were easy, everyone would be doing it) then you may only be able to do a low-rez recording via the Composite Video (YELLOW + RED/WHITE) output.
Hauppauge HD PVR is specifically designed to record Hi-Def from Component Video I/F from Cable/Sat Boxes to PCs onto DVD/BluRay Disk:
Firewire (IEEE-1394) output works ONLY on SOME cable boxes on SOME CATV systems, allowing Unencrypted (CLEAR QAM) Hi-Def LOCAL Channels (ONLY) to be recorded to PC or MAC, although it's harder with PC...but I doubt you have time available to read, learn, (also try SA4250HDC) and ultimately figure out whether your system works....or NOT (more likely):
BTW: I KNOW that Firewire works (without stuttering) on my SA4250HDC and an earlier SA3250 TWC-SanDiego Cable Boxes....and stutters on SA8300HD....going to a JVC D-VHS Hi-Def Recorder. D-VHS Recorders (no longer being manufactured) implement the Copy Protect Flag and hence can record nearly ANY Cable Channel (except ON-Demand and PPV)...whereas PCs can ONLY record the Unencrypted Clear QAM (i.e. Local) channels.
PS: There is (was?) a database of user experiences with Firewire (IEEE-1394) working (or NOT) on various Cable Boxes running various versions of SARA, PASSPORT, NAVIGATOR and OCAP....I couldn't readily find the weblink...so look for it when you peruse the threads cited above.
PPS: Not too long ago the Cable companies convinced FCC to allow them to substitute Ethernet output for the Federally Mandated Firewire output for "Fair Rights" recording purposes....but I haven't run across any info on whether this is a real capability...or a futuristic pipe dream.....Edited by holl_ands - 2/14/13 at 12:01pm