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CableCARD Operation

Discussion in 'TiVo Series3 HDTV DVRs' started by Marconi, Sep 11, 2012.

  1. Marconi

    Marconi TiVo Junkie

    444
    0
    Sep 8, 2001
    Page, AZ USA
    I have a THD (TCD652160), bought used on eBay that I cannot get to receive all digital channels. I'm hoping it's not a TiVo problem, indicating I bought a lemon.

    The CableCARD *seems* to be working but only one channel in the 300-range (non-HD digital) is working and only half of the channels in the 400 range (the HD channels) work. The missing channels all show that the signal is there and the tuning is locked -- it gives all the appearances that the CC has tuned the signal and is working properly, all except there's no picture and sound. My other THDs receive these channels just fine.

    If I understand a CableCARD (CC), it's much like a set top box in that it decodes the signal and hands the audio/video off to the receiver, in this case, a TiVo DVR.

    So why would it decode and display only some channels and not all the channels I should be receiving? Is there *anything* in the DVR itself that could cause this problem? Bent pins in the CC slot? Burned out components? I had them check the permissions for receiving these channels and they assured me that the CC is configured to receive all the channels I'm not getting.

    I'm on my second CC now and it receives the same channels as the first CC did.

    Interestingly, over the weekend, with their tech support on the line, I swapped in a known good CC from one of my other THD boxes and the suspect THD worked properly after re-doing the pairing (unless my recollection is bad!). That's why I picked up a different CC from the Cable Co office yesterday. But it works no better than the one I returned. (Note that this caused crashing on the good THD from which I borrowed the CC once I put the CC back in!)

    So I'm very curious if this could possibly be a THD DVR problem and not a CC problem.
     
  2. dlfl

    dlfl Cranky old novice

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    Jul 6, 2006
    Near...
    If the suspect TiVo worked OK with one CC, doesn't that pretty well prove the TiVo is not the problem? Apparently your cable system doesn't need Tuning Adapters (i.e., doesn't use SDV) -- at least you haven't mentioned that factor. If so that's a good thing.

    Not that it's important for your situation, but my understanding is the CC's don't process the signals. Rather they (if properly authorized by the cable system) provide decryption keys to the TiVo that allow it to process (decrypt) the signals.

    Improper provisioning (i.e., not sending the correct signals to your CC) is the most likely suspect here. What cable co do you use? They probably don't have the account for your suspect TiVo set up right.

    Or -- maybe you've had two bad CC's in a row!
     
  3. Marconi

    Marconi TiVo Junkie

    444
    0
    Sep 8, 2001
    Page, AZ USA
    Yes, if my recollection of that is accurate. I gotta tell ya, when the replacement card failed to work for me, I began to doubt my memory.

    Ah, I guess I didn't properly understand what CableCARDs do.

    I asked about that, specifically, since a couple of years ago they had trouble getting my original CCs to work because they were not properly enabled at the head end. When I asked, they (Cable One) assured me that their end was fine this time. (I hope not)

    That just seems highly unlikely. I'm still hoping the problem is indeed at their end and they'll figure it out eventually.

    When I got my two THDs two years ago, the local office had never installed a CableCARD for anyone before. Because I'd read all about it on line, I knew more about what we needed to do than the technician they sent out. The branch manager accompanied the tech because he too knew nothing about CCs.
     
  4. Marconi

    Marconi TiVo Junkie

    444
    0
    Sep 8, 2001
    Page, AZ USA
    Well, I've just gotten off the phone with their tech support (they called me) and they said they checked everything and could find no problems on their end. They suggested I "call TiVo."

    As it turns out, there's no need as whatever they did fixed the problem.

    I don't know if repeatedly issuing the pair command did it or if someone found an error and, rather than admit to it, just silently corrected it such that the problem was mysteriously solved. In any case, something they did fixed it and I'm a happy customer again.
     
  5. dlfl

    dlfl Cranky old novice

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    Reassuring to see how they have everything under control, isn't it? ;)
     
  6. unitron

    unitron Active Member

    16,390
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    Apr 28, 2006
    semi-coastal NC
    I just read something on another thread that suggested an HD without the latest version of the software might have that problem, so it could be that you bought one that hadn't connected to the mothership in a while and it finally got around to downloading and installing the latest version.
     
  7. SCSIRAID

    SCSIRAID Active Member

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    Feb 2, 2003
    Vero Beach, FL
    To be completely accurate (cause Im just that way lol), the cablecard does the decryption of the cableco mpeg transport stream using the cableco's proprietary encryption scheme (called CA encryption by the spec - Conditional Avaliability - Cisco's system is called Powerkey). It then reencrypts the stream with a key negotiated with the TiVo. This is called CP (Copy Protection) encryption. TiVo has to decrypt it and then reencrypt it again for storage on the harddrive.
     
  8. dlfl

    dlfl Cranky old novice

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    Jul 6, 2006
    Near...
    Thanks. I stand corrected. If SCSIRAID says it, it's true! Reading this description my reaction is "geez there must be a simpler way to control access to a signal!". However, as I think you've pointed out before, the hardware needed to do these encryptions/decryptions is not that massive.
     

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