How to: Change channels directly on Comcast DTA

[sagenewbie]

Hi all,

Like so many of us, I was forced to use the comcast DTA boxes when they recently ceased broadcasting most of their channels in the clear over QAM in my area. In my case, I’m running two Hauppauge 1600 cards, and so used a splitter to feed two DTA boxes to the analogue jacks on the 1600s, while also keeping the two QAM jacks on the 1600 connected to the raw cable feeds (for HD locals).

I will say that the quality of the DTA feeds is acceptable, though not as good as what I previously could tune over QAM. I did find that just a bit of tinkering with the contrast and brightness settings for the Hauppauge cards (through the tuner settings in SAGE) helped with the clarity of the picture, but everything still has just a tiny gaussian blur to it. Afraid that’s the best it will get. People with higher end desires and the money to pay for them will need to go the HDPVR route I guess.

Anyhow, the main point of this post is to note that you can directly control the DTA boxes for channel changes without having to use blaster / receiver cables between your computer and the DTAs. Handily, these DTA’s (and I think this is true of all models, whether Motorola / PACE or Thomson) have a female 1/8th inch jack on the back which is meant to allow you to attach an external IR receiver (which also ships with these units). What most folks have done is used Sage to send channel changes to an IR blaster cable, and controlled the DTAs that way. Though that does work, I wanted something more reliable and direct for my Thomson DTA.

If you want to go this route, the first thing to note is that while Hauppauge cards do generally support IR blasters, they seem incapable of emulating the codes for the DTA boxes (and are limited to controlling only one set top box in a multi-tuner system anyhow). I tried and tried to find a workaround to no avail and I suspect other tuner cards will have the same problems. So you’ll need a USB-UIRT. Sage sells them, as do others on the net. This great little box (read more about it in the forums) can learn the codes from the comcast remote control that came with your DTA and emulate them just fine for channel changes. Handily, on the back of the USB-UIRT is also a female 1/8th inch stereo jack which is meant to feed up to two IR blaster cables (one on the “left” pole of the jack, the other on the “right”, and a common ground).

Now wouldn’t it be great if you could just hook up the blaster jack out from the USB-UIRT directly to the IR receiver jack in on the DTA, and obviate all that blinky-flashy IR stuff in the middle? If so, you’d have the equivalent of a serial connection between sage and the DTA. Well, you *can* do this! The trick is that you need a special little optical resistor thingamajig hard wired between the two.

I wondered if anyone had created such a connecting cable – and sure enough, found a great guy on ebay who was selling just such a cable for comcast victims who use slingboxes and tivos. I sent him the specs on the USB-UIRT and he turned around and made me exactly the connecting cables I needed. Please note I am not him, and I am only posting this to repay the extra time he spent with me to create a solution. They work like a charm, and now that I’ve got it all set up, my channel changes are *rock solid*.

So if this sounds like something worth trying to you, here’s what you’ll need:

1) USB-UIRT

2) A 1/8th stereo to dual mono 1/8th splitter cable. This is necessary to separate the two feeds available at the back of the USB-UIRT. Such a cable is available here:

http://www.audiogear.com/Audio-Adapters-Miniplug.html

Scroll to nearish the bottom of the page. You want: “Stereo Mini Plug Y'd to Left and Right Mono Mini Jacks (all 3.5mm or 1/8")”


3) One (or two, depending on the number of DTAs you want to control) special IR patch cables. These are available from Gary Gray on EBAY, here:

http://myworld.ebay.com/g-gray/

Place an order for the slingbox to Comcast DTA cable. When you place your order, tell him you are actually using a USB-UIRT to control a Comcast DTA box. Specify that the USB-UIRT side of the cable needs a 1/8th inch mono jack, and that the DTA side needs a stereo 1/8th inch jack. He’s now familiar with this.

Next:

Read these posts for some general orientation:

http://forums.sagetv.com/forums/showthread.php?t=46659

http://forums.sagetv.com/forums/show...8916#post48916


My thanks to the authors of those posts! A couple further notes. I found that the .ir files they kindly provided did not work for me – probably because there are subtle differences from one DTA to the next. Here’s an outline of what worked for me:

1) Shut down sage and service. Install drivers for USB-UIRT before plugging it in.

2) If your sage rig currently has any channel remaps (whether for QAM or otherwise), you may need to clear these from your properties file before proceeding. If you find that the USB-UIRT is changing the channels, but seems to do so in an utterly random fashion, previous channel remaps are likely the culprit. I also think it advisable to remove *all* current tuners in “set-up video sources” before proceeding. But you can skip these steps and see if you get lucky first. If not, come back here and start over.

3) Plug in USB-UIRT and start sage. Add a new source (external set top box, channel 3) and proceed as directed in the posts above. After telling Sage you’ll be using the USB-UIRT, you should land at a screen which asks you to name the device (call it something like comcastDTA1). Then you’ll be prompted to point your comcast remote directly at the USB-UIRT and one by one, to push the zero – nine buttons. Do this, and finish setting up the cable line up of your choice.

4) Once finished with the source setup, go to the program guide in Sage and test whether the UIRT is now able to use its onboard IR emitter to change the channels on the DTA. Do so by pointing the front face of the UIRT at the IR receiver provided with the DTA. Run through all of the channels in sage. If every channel changes, you are set to go on to the next step. If you are getting utterly random channel changes, go back to step 2. On the other hand, if you are getting some channels right some of the time, you more likely to need to change the timing and repeat count settings in the IR text file. Using notepad, open: Sagetv/common/remotecodes/USB-UIRTtranceiver/(the device name you assigned, like comcastDTA1.ir). Replace the single opening line with the following two lines:

(your device name followed by a single space) 0 0 0 500 3000 Enter
RepeatCount 2

The next line under RepeatCount2 should be a long string of IR codes for each channel digit – leave these alone, they are the codes the USB-UIRT learned from the comcast remote. Remember to save the file in notepad. Restart sage and see if channel changes are now working. If not, remove the source and try re-learning the codes. You can also try out different settings for timings and repeat codes in the sage interface, but the ones I provided above have worked for several of us.

5) As of now, the USB-UIRT should be sending the correct IR codes via the emitter on its front panel. We need to redirect those codes to the jack on the back of the USB-UIRT. To do so, open up the working .ir code file as you did in notepad in step 4. Here’s what my file looks like before and after being modified to use the back jack:

This…

comcastDTA1 0 0 0 500 3000 Enter
RepeatCount 2
0 0000 0069 0000 0024…
1 0000 0069 0000 0024…
2 0000 006A 0000 0024…
…Continues for each channel number to 9.

Becomes this:

comcastDTA1_Zone1 0 0 0 500 3000 Enter
RepeatCount 2
0 Z10000 0069 0000 0024…
1 Z10000 0069 0000 0024…
2 Z10000 006A 0000 0024…
…Continues for each channel number to 9.

Note the addition of “underscore Zone1 ” to the device name. And note the addition of “ (space) Z1” after every channel number and directly preceding the actual codes.

Save the new version of the .ir file and restart sage. A handy test of your work is to insert a pair of earbuds into the 1/8th jack on the back of the USB-UIRT. Change channels a couple times, and each time you should hear a loud tone coming from one of the earbuds. If so, you are almost done!

6) Insert the 1/8th stereo to mono splitter cable into the jack on the back of the USB-UIRT. Use your earbuds again to verify which side the signal is being output to. Now connect the mono end of the special cable from Gary to the side carrying the signal. Connect the stereo end to the DTA. And voila!

7) (optional) You can configure a second tuner and DTA by following these instructions again. Make sure to give the second IR device a unique name (e.g. ComcastDTA2) and this will create a separate IR file for your second DTA box. When you get to step 5, use “_Zone2” and “ Z2” when you edit the files. The signal will then appear on the second mono jack of the stereo splitter cable.

Others more experienced than I may have simpler or more direct ways of getting this all up and running – if so, please add your notes to this thread and help me to pay it forward.

Good luck, and thanks to all involved in helping me solve this!

--Steve.

[darcilicious]

I will say that the quality of the DTA feeds is acceptable, though not as good as what I previously could tune over QAM. I did find that just a bit of tinkering with the contrast and brightness settings for the Hauppauge cards (through the tuner settings in SAGE) helped with the clarity of the picture, but everything still has just a tiny gaussian blur to it. Afraid that’s the best it will get. People with higher end desires and the money to pay for them will need to go the HDPVR route I guess.

That's because the output of the DTA is analog, not digital like you were getting with clear QAM. Switching to just a HDPVR won't help -- you would also have to get set-top box that provides better quality output, namely component. (But maybe you already knew that? )

[MattHelm]

Wow, thanks, I think you just saved me a TON of hard work.

Can you tell me if this also works on the HD Motorola box? It has a IR port also.

[sagenewbie]

Originally Posted by darcilicious

That's because the output of the DTA is analog, not digital like you were getting with clear QAM. Switching to just a HDPVR won't help -- you would also have to get set-top box that provides better quality output, namely component. (But maybe you already knew that? )

Painfully aware of this. The change in comcast's broadcasting means that to retain digital quality for all stations (as we had over clear QAM before) means not only buying a HDPVR, but paying a monthly rental fee for one of their higher end set top boxes. For me, I can live with the loss in quality with their free DTA boxes (though boy is this silly... they send a digital signal, the DTA dumbs it down to analogue, and then the hauppauge card re-digitizes). The bigger loss for me is file size. The transport streams I used to capture over qam resulted in darn good quality (not HD of course, but really, darn good) at small file sizes (about 1.2 GB per hour). To get anywhere near equivalent quality off the DTA analogue feed, my hauppauge cards require almost twice that. Now *that* I am not happy about. But I suspect I am in good company. Even beyond the HTPC community, think of all the people with qam tuners built right into their TVs who now have to use comcast boxes and remotes or spend hours of time coming up with a work-around. Ugly.

[sagenewbie]

Originally Posted by MattHelm

Wow, thanks, I think you just saved me a TON of hard work.

Can you tell me if this also works on the HD Motorola box? It has a IR port also.

I think it very likely that you can achieve the same results. Things to think about or check on:

1) I don't know what tuner(s) you have in your rig, but assuming hauppauge, it may well be the case that they *can* control your motorola box via blaster. The DTAs I am controlling use a strange IR protocol that only the USB-UIRT seems to be able to handle... But perhaps your set-top box uses a standard protocol. Just be aware that with hauppauge cards you can only control one set-top box in a given system, even if you have more than one hauppauge card (you can find more about this in the forums). And if you are using some other kind of capture card(s), may as well play around first and see if you can get them to control your motorola box using their blasters. Point being, the USB-UIRT is great, but it does run you about 50 bucks. You *may* be able to get by without one. ***In theory***, it should be possible to hard wire any blaster "out" port to any IR receiver "in" port using the kind of cables Gary can make. Whatever route you take, a good rule of thumb is to first get the system up and running well with a blaster cable and an IR receiver between the computer and the set-top box. *Then* replace all those blinky-flashy cables with the single hard wire connection.


2) If you do go with a USB-UIRT, the process of learning your motorola box codes should be similar to what I described, as should setting up one (or two) zones at the back jack on the UIRT. However, the timing and repeat codes I recommended in my post will likely be wrong. You may need to experiment with different settings to get it up and running (and there is a way to try these out in the Sage interface -- don't remember where that screen is buried, tho.)


3) Once you've sorted through all the above, you will want to order the appropriate cable(s) from Gary. To do so, you need to know what kind of jacks you have on both ends of the cable he will make up. The IR in jack on my DTA is intended to receive a 1/8th inch *stereo* feed, while the output from my USB-UIRT is 1/8th inch mono (after using the splitter cable I described before). So you need to know both the dimensions (and be careful here, the hauppauge cards are actually tiny little jacks, smaller than 1/8th) of the ports and whether they send / receive a stereo or mono feed. Tell Gary what boxes you are controlling and what cable ends you need. His prices are very reasonable, so if this does not work, you won't lose too much scratch.

4) If indeed I have saved you a ton of work, can I ask you to do the same for others? If you get this up and running with your rig, could you post just a few notes here on what you needed to do to get it working? Thanks!

[VikingCrown]

2 questions:

1. Is there any way to make Gary's cable work with a Pace DC50X plugged into the Hauppauge 2250's ir port? or is the USB UIRT a necessity?

2. Related but possibly for another thread...If I only want 1 DTA and the QAM signal as well for whats left of the unencrypted, can I use a simple 2-1 signal splitter (since the 2250 only has 1 coaxial input) or do I still need to pick up a channel combiner?

[ace007]

I purchased one of Gary's cables to hook go from the USB-UIRT to Comcast's DTA and its very pretty well. With the exception of just a couple of channels the channel changes are very reliable.

I still have no idea why but there are a few channels that do all kinds of wierd things when it tries to change channels entering extra and incorrect digits. The wierd thing is that other channels using the same digits but in different combos work fine. Have not figured that out yet but i general the cable works pretty well.

[sagenewbie]

Originally Posted by VikingCrown

2 questions:

1. Is there any way to make Gary's cable work with a Pace DC50X plugged into the Hauppauge 2250's ir port? or is the USB UIRT a necessity?

2. Related but possibly for another thread...If I only want 1 DTA and the QAM signal as well for whats left of the unencrypted, can I use a simple 2-1 signal splitter (since the 2250 only has 1 coaxial input) or do I still need to pick up a channel combiner?

Viking,

Before I went down this road, I scoured the forums and googled like mad to see if *anyone* had had success controlling either the pace or thomsen DTAs with a hauppauge product and blaster... no one seems to have, and I believe this is due to a limitation in the hauppauge IR program. Gary's cables will not overcome this limitation. If you can't get it to run with an IR emitter and the IR receiver that comes with the DTA, Gary's cable won't fix it for you... It is merely an electronic by-pass to the IR part of the chain. If you have a spare IR emitter that came with your hauppauge card, you can *try* to get it working, but I think your chances of success are quite low. I think you need a usb uirt.

As to second question, I don't know the 2250, but I'm sure someone else knows the definitive answer. Isn't that card designed tune multiple signals off a single coax line input? If so, then yes, I *think* you should be able to combine the raw feed from the street with the output from the DTA, since the latter is just an analogue dump. You shouldn't take my word for this, but fortunately it is cheap to find out -- just throw a splitter in and see what you get!

Good luck!

[sagenewbie]

Originally Posted by ace007

I purchased one of Gary's cables to hook go from the USB-UIRT to Comcast's DTA and its very pretty well. With the exception of just a couple of channels the channel changes are very reliable.

I still have no idea why but there are a few channels that do all kinds of wierd things when it tries to change channels entering extra and incorrect digits. The wierd thing is that other channels using the same digits but in different combos work fine. Have not figured that out yet but i general the cable works pretty well.

Ace,

Do you have any channels remapped in your setup? I had a similar issue to yours at first, but when I cleared out all the channel mappings from the properties file and started from scratch adding the tuners 1 at a time, the problem went away.

Also, strangely enough, you might try having the UIRT re-learn the codes another time or two in Sage. Each time, keep a copy of the remote codes Sage captures (in notepad -- as I explained earlier.) Compare them. I found that they were not identical each time, and some worked better than others. In the end, I pieced together several files, choosing the best channel codes captured from each.

Beyond that, you got me. The good news in all this is once you do get the channels correct, it really becomes bulletproof, and you don't need to keep messing with it. At least, that's been my experience thus far. I've been running two DTAs for a month now and not a single missed recording.

Thanks for chiming in, and if you get the last wrinkles sorted out, please let others know how you resolved it. There are a LOT of us who have had to make this transition, and mores still coming as comcast continues converting...

best wishes to you...

[Ice|Burn]

I have a related, yet unrelated question and I didn't want to start a new thread for it.

I just have one DTA I'm looking to control from my USBUIRT. Can I just go pick up a male to male 1/8th inch stereo cable and call it good? Or do I need a mono cable instead?

[SHS]

Hay Steve as for

3) One (or two, depending on the number of DTAs you want to control) special IR patch cables. These are available from Gary Gray on EBAY, here:

http://myworld.ebay.com/g-gray/

Place an order for the slingbox to Comcast DTA cable. When you place your order, tell him you are actually using a USB-UIRT to control a Comcast DTA box. Specify that the USB-UIRT side of the cable needs a 1/8th inch mono jack, and that the DTA side needs a stereo 1/8th inch jack. He’s now familiar with this.

That g-gray is nothing more then a rip off con artist with so call special IR patch cables.
It not more then a standerd 1/8 stereo jack where the TiVo one is nothing more then a 1/8 stereo jack to 1/8 mono jack

[SHS]

Originally Posted by VikingCrown

2 questions:

1. Is there any way to make Gary's cable work with a Pace DC50X plugged into the Hauppauge 2250's ir port? or is the USB UIRT a necessity?

2. Related but possibly for another thread...If I only want 1 DTA and the QAM signal as well for whats left of the unencrypted, can I use a simple 2-1 signal splitter (since the 2250 only has 1 coaxial input) or do I still need to pick up a channel combiner?

Being all IR emmiter work the same way there should be no reason why the Hauppauge 2250's ir port wouldn't work as well.
May guest would be cut IR emmiter off and replace it 1/8inch jack

[SHS]

Originally Posted by darcilicious

That's because the output of the DTA is analog, not digital like you were getting with clear QAM. Switching to just a HDPVR won't help -- you would also have to get set-top box that provides better quality output, namely component. (But maybe you already knew that? )

It ever bit as bad as old over air tuner
Any way steve you better of just leasing real cable box what going cost a few more dallor.
Here I on TWC and it cost more vs 1st Digital cable box which free but cost a few more buck for 2nd box and so on.

[Fuzzy]

A real SD cable box WOULD get you much better picture quality, connected via S-Video, than you are going to get from the DTA. A lot of the blurring is the poor quality modulation in those DTA's. They have NO incentive to make them any good PQ wise, as there has to be sone incentive to move to the better boxes (even the SD ones).

[KKnox]

Originally Posted by SHS

Hay Steve as for

That g-gray is nothing more then a rip off con artist with so call special IR patch cables.
It not more then a standerd 1/8 stereo jack where the TiVo one is nothing more then a 1/8 stereo jack to 1/8 mono jack

I suspect that SHS is correct about this. Can anyone verify this? Has anyone tried a standard 1/8" patch cable?

[korben_dallas]

I read a posting in the USB-UIRT forum where someone asked this same question, and the guy who makes the USB-UIRT said he suspected you might actually damage your STB with a straight cable.

[aedgington]

I tried this and my Sage service instantly crashes when I test channel changes. What could I be doing wrong?

[jhkoenig]

Add a 10K resistor into the straight cable (in series, not parallel) and everything should work fine. Sorry g-gray, but it just isn't that hard.

[ranger]

Originally Posted by jhkoenig

Add a 10K resistor into the straight cable (in series, not parallel) and everything should work fine. Sorry g-gray, but it just isn't that hard.

Does the resistor go to the tip or ring? Or doesn't it matter?

[jhkoenig]

Hey Ranger. The placement of the resistor doesn't really matter, but is traditionally done on the tip side, leaving ring (ground/return) left alone. Won't matter in this application, but in other situations putting resistance on the ground side can get you hurt. Good luck!