Nothing that I can remember, I had my machine upstairs in my computer room and the set top box in the living room, all I did initially was run a crossover cat5 cable from one of my network cards in my main machine to the back of the STB. I know some of the NTL cabled areas use a separate cable modem box (mine was actually in the STB itself). Once I'd done that I followed the NTL instructions TO THE LETTER! I eventually bought a router (a linksys one) which I got set up in no time at all. Other than that, I've never had the service go down and I use it every day! Or should I say, used to use it, sadly I'll now have to make do with ADSL which, from the reviews I've read, seems to be a real bag of sh*te.
All in all, I've been very impressed with the service NTL have given me (even though their TV service is a bit pants). Hope you enjoy your cable modem, for what I hear even the 512k version (which is what I had) is faster than its ADSL equivalent.
_________________________
Cheers,
Andy M