I think I read the latest iterations of Digital RF signals (QAM tuners via coax) only modulate on channel 3. The black screen on channel-3 was your Cox signal but it appears the QAM tuner in your Dynex only received scrambled programming. QAM tuners only support "in-the-clear" (unscrambled) digital programs, so I guess a black screen is what it looks like. I bet if you surf channel-3 long enough, you'll find something in-the-clear.
As for your recent recording-to-DVD successes, those programs are from your local TV affiliates, such as PBS and whichever local has the broadcast rights for your MLB team. Either the locals are not scrambling their content or Cox doesn't feel those channels are monetarily worth scrambling. I'm sure Cox's decision varies from market-to-market and from time-to-time. After reading this, they'll start scrambling those channels. J/K.
I think the difference between your previous Scientific Atlanta box and the new Cisco box is the support for QAM tuners. I'm not sure how old your previous Scientific Atlanta box was, but I'll guess it was from Cox' pre-encryption days. It wasn't an issue of being "obsolete" but an issue of not supporting encryption, scrambling and copy-right protection. Cox wants to get those vulnerabilities off their networks. Why'd you turn it in?
Label me as "lost in the dark ages", my rhetorical question would be, "what is the purpose of DVD recorders, if not to record TV programming?" I can see how stuff on HBO or pay-per-view might be blocked, but old TCM movies?? How many people are going to skip work to watch "20 Mule Team" at 11:30 am?? My older brother uses a DVR to watch ball games sans commercials, but I imagine there is some kind of arms race going on between what he has and the program makers who make money from advertising. But I have no idea how DVRs work and have no intention of getting one if I can't transport movies out to my elderly mother's place. Is TCM so desparate for money that they want to mandate old folks to get cable TV and watch particular movies at oddball times of the day or get DVRs and learn how those work? My mom can still barely figure out her cordless landline phone.
I turned in the old Scientific Atlantic cable box because it flat out stopped working. I was alerted by Cox twice by mail starting a month or two ago that I might start to lose channels after May 7th if I didn't swap to the newer "Contour" setup, and then recently I started getting online alerts about that in popup windows, which I thought was particularly intrusive. So I called to have the new box delivered and had planned to do the swap in my own sweet time a week or two later after getting it, but then one evening only days after getting the new box, all cable TV stopped working completely, followed right after by the announcement on the screen that my cable service had been disconnected. A call to a Cox rep revealed that they had somehow activated my new Cisco 'system' (without any action prompting that from me) and that in order to watch TV again, I had to install the Cisco box right away. That's were the troubles began, because it should have worked with the way the prior coaxial cables were connected previously to my Magnavox recorder.
I figured out how to see TV by bypassing the DVD recorder with the HDMI cable, but in the email correspondence with Cox Help people on why the signal wasn't working through the DVD recorder, they ultimately suggested that I had a defective Cisco box and that I should exchange it for a different one. When that didn't help, I figured I might find some answers in this online forum, but all that I saw was years out of date on connection problems with DVD recorders. Thus my need to sign in and ask directly toward folks like you guys who know way more better on what's going on. I love no-thinkum plug & play, which this certainly was not.
