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IR to IR w/ Comcast's Digital Transport Adapter (DTA)

Discussion in 'TiVo Help Center' started by blobly, Aug 5, 2009.

  1. Aug 5, 2009 #1 of 122
    blobly

    blobly New Member

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    Aug 5, 2009
    As most of you know Comcast is going all digital and will require some sort of box to view all your channels. The simplest form is the Digital Transport Adapter (DTA) which Comcast sent me 2 for free with my account.

    I have not set them up yet, but pulled them out of the box and look at the instructions. The DTA I have has an IR input on the back with an IR receiver in case, according to the directions, you want to hide the box behind your tv.

    I have a S2 Tivo, and on the back it has an Ir out, obviously to use with the IR emitters to control such cable box. My question is, can I bypass using the Tivo IR emitter, and just get a cable to connect the Tivo IR out directly to the DTA IR input? In theory it seems like it should work - but I don't have the cable to try it.

    (I have already upgraded our main viewing room to a Tivo HD, but want to keep the old tivo for the bedroom)
     
  2. Aug 5, 2009 #2 of 122
    pdonoghu

    pdonoghu New Member

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    Mar 5, 2003
    Upper...
    No, that will not work and might even cause damage to the devices due to differing voltages. I've seen a report where someone built an optical isolater to connect the two devices, which might be a slightly cleaner looking setup than the Tivo IR blaster cable and the Comcast DTA IR extender. Best bet, set it up with the cables provided, and hide the DTA behind the TV or Tivo.

    If by chance you have a dual tuner Series 2, you will be better off with a cable box over the DTA as you can retain some dual tuning functionality for the remaining analog channels.
     
  3. Aug 5, 2009 #3 of 122
    GGray

    GGray Member

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    Nov 15, 2006
    Long time lurker, first time poster.

    I also had to recently convert to the Comcast DTA.

    I was missing an IR Blaster from one of my TiVos, so I designed and built and adapter to do exactly what you describe. I have a web page describing the cable, but I can't post a link because on my low post count. If you're interested, drop me a note and I'll email the details.


    Gary
     
  4. Aug 5, 2009 #4 of 122
    blobly

    blobly New Member

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    Aug 5, 2009
    Yes I would, can you send me a private message with the link?
     
  5. Aug 5, 2009 #5 of 122
    classicsat

    classicsat Astute User

    17,877
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    Feb 18, 2004
    Ontario Canada.
    A few K of picture is worth 40 words.

    You need a 1/8" to 1/8" stereo patch cable, and a transistor optocoupler, and optionally a small perf board.

    Cut the cable in two.

    On the LED side with one end of the cable, connect the tip to LED positive (anode, usually pin 2), sleeve to LED negative (cathode, usually pin 1)

    On the transistor side, with the other end of the cable, connect sleeve to transistor emitter (usually pin 4), and ring (middle connection) to transistor collector (usually pin 5).

    Leave the other optoisolator pins and cable wires unconnected but secure from shorting.

    Mark the ends to make it clear which end is which, for if you plug the wrong end into the wrong place something will, or at least could blow.
     
  6. Aug 5, 2009 #6 of 122
    GGray

    GGray Member

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    Nov 15, 2006
    I took a slightly different approach using a MOSFET and a couple of resistors.

    It's useful to note that the TiVo and the DTA share a ground through the shield of the coax cable conecting them.

    I'm happy share my design with anyone interested, but I can't post a link yet.


    Gary
     
  7. Aug 5, 2009 #7 of 122
    blobly

    blobly New Member

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    Aug 5, 2009
    I bought 2 cables from GGray on ebay - I will post my results once they are installed
     
  8. Aug 5, 2009 #8 of 122
    gastrof

    gastrof Hubcaps r in fashion

    7,479
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    Oct 31, 2003
    Potato and pen.
    I'd be interested in seeing the eBay page. Are any more such cables available?
     
  9. Aug 6, 2009 #9 of 122
    blobly

    blobly New Member

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    Aug 5, 2009
    grayeng.net/TiVotoComcast.htm

    cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320408732826#ht_500wt_924
     
  10. Aug 6, 2009 #10 of 122
    GGray

    GGray Member

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    Nov 15, 2006
    Bobly,

    Thanks for posting the partial links. I'm not sure the EBay link conforms to TC posting guidelines. It may be considered spam. Maybe someone else could clarify this. The first link is more of a "how-to", and I think it is fine.

    Gary
     
  11. Aug 11, 2009 #11 of 122
    blobly

    blobly New Member

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    Aug 5, 2009
    Got the cables from GGray
    They work great!!!

    Thanks
     
  12. Aug 11, 2009 #12 of 122
    GGray

    GGray Member

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    Nov 15, 2006
    I'm glad to hear the cables are working out for you.


    Gary
     
  13. Aug 13, 2009 #13 of 122
    chakk

    chakk New Member

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    Mar 27, 2008
    Since I had to connect TWO DTAs -- one for the TV and one for the Tivo positioned in the same media cabinet as the TV -- I positioned the 2 Tivo IR blasters next to the RF receiver extender that came with the DTA, wrapped the three of them together with duct tape after verifying that the IR blasters were working correctly, and then taped a small piece of aluminum foil over the IR receiver window on the Tivo's DTA box. This prevents the DTA remote that is controlling the TV's connected DTA box from accidentally also changing the channels on the Tivo's DTA box. Plugging the IR receiver extender into the back of the DTA merely adds a second IR receiver site to the DTA box -- it does not disable the IR receiver on the DTA box itself.

    I also put a piece of black electrical tape over all of those #$#@^$! green LED lights on all the DTA boxes -- they serve no purpose other than to inform you that the DTA is connected to the cable TV signal. Duh!
     
  14. Aug 13, 2009 #14 of 122
    blobly

    blobly New Member

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    Aug 5, 2009
    the cables from GGray are working fine and were a cheap easy solution
     
  15. Aug 13, 2009 #15 of 122
    edubbrulez

    edubbrulez Member

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    Mar 4, 2004
    SE, PA
    I would like to try and build one of these cables. GGray - can you provide a parts list and instructions on how to assemble?
     
  16. Aug 13, 2009 #16 of 122
    classicsat

    classicsat Astute User

    17,877
    0
    Feb 18, 2004
    Ontario Canada.
    http://grayeng.net/TiVotoComcast.htm
    The parts are in the schematic. 2x 10K resistors, BS107 FET transistor, 1/8" mono and stereo plugs and cord. A stereo 1/8" patch cord is fine.
     
  17. Aug 13, 2009 #17 of 122
    edubbrulez

    edubbrulez Member

    431
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    Mar 4, 2004
    SE, PA
    Thanks. I'm not familiar with EE schematics.
     
  18. Aug 25, 2009 #18 of 122
    Bill McNeal

    Bill McNeal Member

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    May 31, 2002
    Does anyone know if these cables work for other Comcast STBs (such as the Motorola or HD box), and for the S1 as well?
     
  19. Aug 25, 2009 #19 of 122
    GGray

    GGray Member

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    Nov 15, 2006
    Since I have only tested the cable on Series 2 TiVos with the Pace DTA, I can't say for sure, but perhaps some other users can help fill in the blanks.

    Here are the important questsions:

    Are the IR Blasters interchangeable for Series 1 and Series 2 TiVos?

    Do other Comcast STBs have an input for a remote IR sensor and, if so, is it also a 1/8" stereo plug?

    Gary
     
  20. Aug 25, 2009 #20 of 122
    Bill McNeal

    Bill McNeal Member

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    May 31, 2002
    I'm assuming the answer to the first question is yes, given that Tivo only sells one type of IR control cable.

    Visually on the boxes I have (Comcast HD and black Motorola), it looks like the answer to the second question is also yes. But I don't know if there are other issues than jack size that may complicate compatibility, such as voltages and such.
     

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