Charter has never used ATSC so it is a pretty good bet that your ViP612 has never tuned (and will never tune) Charter.Ok, so it's the Qam that prevents it. When I first got my 612's Charter must have had (or still does) ATSC because I certainly could at that time, it was free with internet connection.
The TV at work is at least 10 years old, perhaps older. Would it be capable of getting clearQam signals from cable?. It gets Charter basic with no box.
The answer to your older TV or your ViP612 getting QAM (clear or otherwise) is NO.
You would need to replace the TV with one that has a QAM tuner (cablecard is not necessary), add a QAM capable DVD recorder, late model TiVo or use a cable box to get clear QAM. In no case will you be able to tune or record the content with your ViP612.