I put the question mark in the title because I'm not 100% where the problem is actually occurring, but I'll do my best to explain it.
My set up(my cable is through Charter) is the cable from the wall goes in to the cable box(which, as stated in the title is a motorola dcx3501-m), and I have an HDMI cable going from my cable box to the TV. The problem is that, at random times, my TV will flicker on and off in like 2 or 3 second intervals and the cable box will display "dui" where the time usually is. It will continue flickering on and off, and the cable box will keep switching from the time display to that "error message" anywhere from a minute, to I've had it go as long as 15 minutes til it finally straightens itself out and the TV returns to normal. Also, while it's going through this error, the cable box keeps switching between the different HD resolutions(1080,720), noted to the right of the error message/time display. I also should note that when the error isn't occurring, the picture quality is fantastic/have no problems with any of the TV or cable box options.
While the TV is doing this flickering on and off, there's nothing I have found I can do to stop it. I can't turn it off(with either the remote or the button on the TV), turning off the cable box doesn't stop it(the cable box shows that it's not on, but the TV still flickers), etc, etc. From the reading up I've done this is supposed to be some kind of "handshake" error. I've tried using all the different HDMI ports on the TV, and that hasn't fixed it. I've also tried different HDMI cables, no luck there either.
I've tried the turning off the power box/accessing the menu, and setting the default as 1080p, 1080i and 720p. The error has occurred on all 3 settings. My TV is an LG LCD 42 inch SmartTV, if that has anything to do with it.
Hopefully I'm posting this in the right section, if not I do apologize, but it seemed to be the right one.