TiVo Community Forums Archives - Serial cable usage with Digital Cable box

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Serial cable usage with Digital Cable box
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Posted by: MonsterTrosity

I have a GI (General Instrument) digital cable set-top box that has two serial jacks, and an IR jack. My TiVo unit is a Philips, but did not come with a serial adapter that fits my set-top box. All 3 inputs are mini-phono, and am curious if a standard mini-phono to mini-phono cord would work, and if so, what port do I put it in? The data jacks are labeled "HIGH SPEED", and "OUT OF BAND". Is there also something I need to configure on my TiVo unit?

Any help is appreciated.

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Möns†er†rosi†y

Posted by: Spire

The TiVo serial connection does not work with any cable boxes. Just use the built-in "eye" IR blaster, and if that fails to work reliably, the external IR blaster.

Posted by: Raech

This is a FACT. I even have a Philips digital cable box, but it won't work with the serial port. Basically TiVo needs to write into the software for a cable box connection to be able to use thsi port. It has not as of yet. SO only sat tv systems like DSS use them for now.

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It's all in how you look at it

Posted by: MonsterTrosity

Wrong. I've got it to work. What you need to do is cross the phono cables.

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Möns†er†rosi†y

Posted by: Mike Lang

Wrong! Put your hand over the IR emitter in the front of the TiVo and the cable you "think" is working will stop. Hmmm...

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Mike Lang
Moderator: TiVo Coffee House, Tips & Tricks, Open User Surveys Forums

Posted by: Serra

quote:
Originally posted by MonsterTrosity:
Wrong. I've got it to work. What you need to do is cross the phono cables.

Did you try Mike's thing? Does it still work?

Posted by: MonsterTrosity

Hi Serra,

I haven't as of yet, had a chance to look at Mike's suggestion, but I can tell you what I've tried, and what works. Basically, I've taken a male stereo mini-phono adapter to male rca adapter, and mated them with another adapter that is female rca to mail mini-phono adapter. The trick here is that you need a crossover for the communications to work properly. What I did to accomplish this is to simply swap the red for the white RCA connectors. In other words, instead of having the standard left mate with left, and right mate with right, I swapped the stereo plugs, and thus created a mini-phono to mini-phono crossover cable without any soldering or splicing of the wires.

And it works great!

Hope this helps.

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Möns†er†rosi†y

Posted by: MonsterTrosity

BTW,

I have removed my IR cable completely, so there is no possible way it could be the IR that is changing the channels http://www.avsforum.com/ubbtivo/wink.gif.

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Möns†er†rosi†y

Posted by: holee

You can use RCA inputs to change cable channels?

How does the Tivo box know to use this? What cable box do you set it as?

Posted by: rbird

quote:
Originally posted by MonsterTrosity:
I have removed my IR cable completely, so there is no possible way it could be the IR that is changing the channels http://www.avsforum.com/ubbtivo/wink.gif.

Actually, the "eye" of the Tivo also sends out IR commands. That's probably what is changing your channels. Cover up the "eye" and try it again.

Bob

Posted by: steined

MonsterTrosity, How did you connect the cable to the serial port on the back of the box? My box has a 9 pin, female connector that looks similar to the s-video port. Did you use an adapter? If so where did you get it? Thanks.

Posted by: MonsterTrosity

Yes, actually, I did cover the IR from the cable box to test it. My cable box is a General Instrament. The box itself knows nothing about the rca inputs, it simply transmits the signal through the cable. The serial adapter on the back of my box is a standard mini-phono, just like that of the TiVo. I tried a basic streight-through mini-phono to mini-phono adapter, adn it didn't work, but using stereo rca allowed me to cross the transmit and receive wires so that is could communicate. I hope I'm not confusing anyone any further http://www.avsforum.com/ubbtivo/wink.gif.

I believe the setting I used was 093 fast for the cable box. It is much faster at changing channels now. Those of you that have a ps/2 style serial input, I suggest you check with the manufacturer to find out which wire is transmit, receive, and ground. Those are the only three wires you would need.

Regards,

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Möns†er†rosi†y

Posted by: Dargon

Clever clever clever! I tried using just a straight-through mini-phono cable and discovered that didn't work, but never thought to cross the wires. If this actually works, it will solve the most annoying problem I have with my tivo.

Thanks for posting!

Dargon

Posted by: 8_ball

I must have missed something. So you're cable from Tivo to set-top box looks like this?

Mini to RCA Male RCA Female to Mini
TiVo ----------------> ------------------>Set Top

Questions:
- Why the RCA connectors, for the cross-over?
- Which port on the Tivo and which port on the Set-top did you use?
- What GI box do you have?

Thanks! When I get the details, I'll try this while blocking the TiVo IR eye and see how it works.

P.S. Richard you've said this is impossible for software reasons. Any comment here?

[This message has been edited by 8_ball (edited 01-02-2001).]

Posted by: MonsterTrosity

8_Ball,

That is corect, only it is stereo. This means that the mini-phono is stereo as well as stereo RCAs. Instead of putting the red rca male to the red rca female, and likewise with the white, I put the red to the white, and the vise versa with the other. This is what creates the crossover, while keeping the ground wire the same. I don't know exactly what my model GI is, but it has two serial inputs, do not use the one that says high-speed.

Hope that helps,

Regards,

Posted by: holee

Monstrosity.

One more time then, just so I've got this right.

You need:
mini-jack -> male STEREO RCA adaptor
mini-jack -> female STEREO RCA adaptor

Plug them together, but swap the red audio
in with the white audio out and vice versa?

So all you need is an adaptor with one mini-jack plug on one end, and two RCA plugs on another end? And then the female version of it?

Posted by: MonsterTrosity

That's correct. Remember though, I have a General Instrament, and it works for mine, it might not work for all units. Also, when you do this, you may be risking electronic shock to yourself, and or the equipment. I won't be held responsible for any damage done to yourself, or your equipment. So if you choose to do this, you do so at your own discression. I'm not saying that there is going to be a problem, but I just need to make sure that I am not puting myself at risk by giving advice http://www.avsforum.com/ubbtivo/wink.gif. Usually, serial interfaces are low voltage, and you are probably not at risk, but it can happen.

Regards,

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Möns†er†rosi†y

Posted by: holee

I've got a General Instruments box too. And it has those holes in the end as well. I think we have similar, if not same boxes (mine is through AT+T Cable).

To be honest, I had no idea those were also serial ports. I always equated serial ports with what's on a PC.

If this works, it'll be cool. And if I get killed doing it, I'll try not to get too upset at you.

Posted by: MonsterTrosity

Yeah, what's particularly interesting, is that you can setup a console cable and see what's happening from a PC. On the TiVo, suposedly, you can change settings from the command line because it is a Linux OS. You have to be somewhat of an expert to do anything with it, however, because the OS is completely redone.

I only tried the RCA trick, because if it were a true serial connector, it would communicate in crossover. I configure routers and firewalls, so I've done this sort of thing many times before.

Good Luck...

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Möns†er†rosi†y

Posted by: tomgrossi

Has anyone gotten this to work? Not to question Monstrosity, but I've been on a few wild goose chases already in search of this holy grail, only to find out that whoever had made the claim had failed to completely cover the tivo's "eye" when doing their tests.

Posted by: Dargon

quote:
Has anyone gotten this to work? Not to question Monstrosity, but I've been on a few wild goose chases already in search of this holy grail, only to find out that whoever had made the claim had failed to completely cover the tivo's "eye" when doing their tests.

I had no luck getting this to work. I checked my cable box's configuration screen and it listed "IR Blast" (the port I tried to use) as disabled, with no way to enable it. That may be enough to cause my system to not work, however...

The IR blaster cable that comes with Tivo is mono, not stereo. That doesn't necessarily mean that the method won't work either (since remote controls are one-way devices), but it does mean that at least half of the crossover cable is unneeded.

MonsterTrosity, I know most people here suggest covering the Tivo's IR emitter or the cable box's IR receiver as a test, but I've fooled myself a couple times that way. A better test is to simply unplug your crossover cable and don't cover either IR emitter. If your Tivo can still change channels that way, it's obviously using the Tivo IR emitter. While your cable is unplugged, experiment with covering the IR emitters until you can get a consistant failure. I have more luck overing the receiver end. Then you can plug your cable back in, cover the emitter the way you know it will fail, and test the cable again.

If it's not too much trouble, please give this method a try and let us know how it goes!

Dargon

Posted by: mishagray

Thank you. I also tried the pass through. I am going to try this trick right away. My cable box is hidden behind my TV away from all IR of all kind except for the Tivo's blaster. I did this after my family kept accidently chaning the channel, turning the box off, etc. Very annoying for Tivo.

Now they can't get to the cable box at all and have to use either the Tivo or the TV's internal cable tuner.

However the IR speed is currently very low (also IR code 93) and makes surfing through the Tivo down right unbearable. Mine is the latest Motorola brand Digial box that Comcast of NJ is using (Motorola bought GI!). I used to have the older model that had the GI brand. both have the "low speed" ir port in the back.

I can confirm whether it should work. Will post after I am done. I might even have all the equipment I need already.

Posted by: holee

Well I tried this out and no go. Sigh.

I also couldn't find a serial port active/deactive setting on my cable box. Maybe there's just too much differences between the GI boxes.

Posted by: rmuniz

Hello all,

I tried the crossover cable, but it does not work. Or maybe I Am doing something wrong?

Here is what I did and what I used.

1 x Sony Tivo 30 hour
1 x General Instrument Digital Cable box model #: DCT 2224/1361/ABCDEF
2 x 3-FT Y-Adapter audio cable - male mini to male phono - RadioShack cat no. 42-2475A
2 x Phono jack to phono jack couplers - RadioShack cat no. 274-874A

I could not find a Y-Adapter cable with female phono ends, so I used the couplers to mate the phono ends of the cables.

Tivo setting for the cable box is set to 093 fast

The GI box has three mini connectors - high speed, out of band and RI. I used the RI connection.

It is connected like so, with the crossover being made in the middle by connecting the red phono ends to the white phono ends of the cables

Tivo cntrl out serial <__mini male__phono male__> coupler <__phono male__mini male__> RI connection on GI box

Rick Muñiz

[This message has been edited by rmuniz (edited 01-10-2001).]

Posted by: holee

rmuniz

I did the exact same thing as you. I even
used the same cables. Although I used the
radio shack phono plug couplers (27-1553a)
but i think they're about the same.

I'm ready to chalk this up to a glitch that
at least one person seems to benefit from, but one that the rest of us will have to live without.

Posted by: rmuniz

quote:
Originally posted by holee:
rmuniz

I did the exact same thing as you. I even
used the same cables. Although I used the
radio shack phono plug couplers (27-1553a)
but i think they're about the same.

I'm ready to chalk this up to a glitch that
at least one person seems to benefit from, but one that the rest of us will have to live without.

I agree. The quest for the Holy Grail continues...

I hope someone finds a way to get the Tivo to control the digital cable boxes soon. The lag in channel changes is unbearable. My wife is so pissed that she wants to scrap the whole thing. I will probably have to do something soon. The Direct Tivo sounds good, but it is an extreme measure just to get the Tivo to work the way it should in the first place.

Rick Muñiz

Posted by: Tom Keels

I also have the new Motorolla dc box and it shows that the IR port is disabled with no way to change it. I assume the cable company (Comcast) has to send a message into it to turn it on. For now I use my dc box seperate from my tivo because surfing is terribly slow.

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"Do not anger Talking Tiki!"

Tom Keels

Posted by: CoosCoos

quote:
Originally posted by MonsterTrosity:
I have removed my IR cable completely, so there is no possible way it could be the IR that is changing the channels.

I'm still not entirely convinced that this works. I know someone else who used a mini-din cable and removed their IR blaster wires and thought the whole thing was working great. But then one day they mentioned that it still missed channels once in awhile . . . which it shouldn't do if it's hard-wired. Then we researched it here in the forum and it turned out you don't even need the IR blaster cables at all because the "HAL 9000" eye on the front is blasting, too. For my setup, the IR cables work better, but the eye still works.

MonsterTrosity, we'd all be in your debt if you could complete the testing as outlined in these posts. Thanks!

Posted by: MonsterTrosity

My appologies. I attempted to completely cover the IR with a piece of black electrical tape, and my box would not change channels. It appears to have been using the IR eye on the TiVo and bouncing it off of the glass back to the cable box. I'm sorry for any inconveniences this has caused anyone. In the near future I'm going to construct a console cable for my pc, and find out what command line options work for changing channels, and also, what the TiVo uses to post channel info through the serial. Maybe at one point we can get a resolution to our slow channel surfing problem. I will be continually hacking, and let you know my results when complete.

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Möns†er†rosi†y

Posted by: CoosCoos

quote:
Originally posted by MonsterTrosity:
In the near future I'm going to construct a console cable for my pc, and find out what command line options work for changing channels, and also, what the TiVo uses to post channel info through the serial. Maybe at one point we can get a resolution to our slow channel surfing problem.

Thanks for the update, and more power to you! You seem dedicated and knowledgeable so hopefully you can find something.

Posted by: rbird

Told ya so! http://www.avsforum.com/ubbtivo/smile.gif (1/2/01, 12:29 pm)

Bob

Posted by: Mike Lang

Me too! (12-28-00 7:28am)

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Mike Lang
Moderator: TiVo Coffee House, Tips & Tricks, Open User Surveys Forums