Here is a good explanation of booting the cable box and what all those strange symbols mean. you unplug and plug the unit. cable box display:
-NU-
(blank) 2-4 seconds
boot
(blank) 1-2 minutes
then time would show up. if it doesn't and 4 lines/dashes appears, call the cable company.

Message from:DSLM

Plus, -NU- and boot both mean cable box starting to boot. but why the scientific atlanta the programmers had to put NU? THAT IS UNKNOWN!!!