Maybe this topic is too minor of a consideration, since it typically either just works or it just doesn't work... But I remember being curious myself as to what all that displayed up on the LCD actually means. I can't be the only person out there wondering what's going on, so I figured it would be good write up something people could understand (even if the specifics are left out because they are A. too technical B. probably proprietary info)
This is public knowledge (which could all completely change in the coming years) for most major cable box manufacturers (i.e.: Samsung, Arris/Motorola, Pioneer, etc.) that sell their boxes to cable companies (Charter/TWC, Comcast, Frontier, Brighthouse, etc.), but I couldn't find but bit & pieces out there on the net. There was actually more info about this on ComCast's forums , but it didn't look like any has ever bothered to explain it in layman's terms what the front of that newer cable box is meaning when it's doing a L-something countdown or gets stuck on displaying "AIT" (and it is AIT, not ALT).
OCAP itself, is middleware designed by CableLabs, it's coded in Java. Hence if you've ever wondered why if you see Java advertising that they are on billions of devices... That's a sizable percentage of them right there.
In layman's terms, think of OCAP being like base-level programing of the cable box, like an operating system of sorts. ODN is the "On Demand Navigator" which is kind like an application running on your operating system. So if OCAP was Windows/MacOSX/Linux, ODN would be like Chrome/Firefox/Safari.
I'm going to try to keep this as non-technicial and avoid proprietary stuff (just the things that are in-common with all cable providers and various brands of boxes), but just a warning, the terminology is very technical sounding... sorry in advance for that, it can't be avoided.
OpenCable Application Platform (OCAP) Boot-up Sequence:
(the part in bold & underlined is what shows on the LCD on the front of the box)
Good explainer, yes written in Java, one of the reasons updated firmware does not run well in old boxes, new firmware(software) is written for later hardware.