# CableCard 2.0



## mlear (Dec 14, 2002)

I read in the FAQ the section that states:

*Does the S3 support CableCARD 2.0?*
_The CableCARD 2.0 specification has not been finalized at this time, so it is not possible to give a final answer. However, the current CC 2.0 proposal requires hardware the S3 does not have. Therefore, the S3, as it stands today, would not be able to support bidirectional communication for CC 2.0 features such as OnDemand or Switched Digital Video. If a 2.0 card is inserted it should fall back to 1.0 with Multi-Stream._

I'm curious what additional hardware would be needed to support on-demand services? I'm not sure this is a dealbreaker, but it would sure be nice to be able to order a football game, or a movie with the S3.

Also, I read on Digg that 2.0 support might be available via a Tivo Software upgrade. Is there any truth to this rumor?

-Matt


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## Krellion (May 17, 2002)

The TiVo would require the hardware that's needed to transmit data back to the cable company, which it most likely doesn't have.


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## classicX (May 10, 2006)

Krellion said:


> most likely doesn't have.


It's fact - the S3 doesn't have the required hardware.

Whether there may be some sort of USB add-on that could do it, only time will tell.


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## tomryan (Sep 9, 2006)

classicX said:


> It's fact - the S3 doesn't have the required hardware.
> 
> Whether there may be some sort of USB add-on that could do it, only time will tell.


That's what I'm hoping for.. a USB add-on, can't think of any reason why it would not be possible.

Of course, what's to stop tivo (as part of their partnership with cox/comcast) from asking them (nicely of course), if the two way comm could come back over the ethernet.. (of course requiring that you have a cable modem setup from them)..

I can't see why they couldn't do that either.. of course, I highly doubt that would happen, but I can dream!


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## HiDefGator (Oct 12, 2004)

It's unlikely Tivo would bother making a USB add-on for the S3. It would be far more logical to put the effort into the new S4 box instead.


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## mbhuff (Jan 25, 2004)

What's more version 2.0 of CC as it stands requires OCAP. Which means tivo would be hardware only and allow the cable companies to download their operating system and user interface to make it work.

The current draft specification makes an idea like a TiVO impossible, rather it will be up to the cable company to determine what you can do and how you do it.


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## Bighouse (Sep 3, 2004)

I don't think I'm going to miss any VOD or PPV or any features that a CC2 would give me that a CC1 and my S3 provides. I never use those and if I do, I've got a STB from my local cable provider that can give me those features.

That's especially true if it meant I'd have to go with the cable company's guide and OS!!!


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## CCourtney (Mar 28, 2006)

classicX said:


> It's fact - the S3 doesn't have the required hardware.
> 
> Whether there may be some sort of USB add-on that could do it, only time will tell.


CC 2.0 will use DOCSIS based modem technology to transmit data back to the head end. After all it has to go back via Cable and CableLabs always uses DOCSIS based designs for this stuff in their specs as DOCSIS is there cable modem specification.

I would seriously doubt anyone would invest in creating an upstream DOCSIS module that would connect up to the USB in the first place. And there's no way in hell that CableLabs would approve such a device in the second place.

So don't even bother dreaming about it.

CCourtney


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## eisenb11 (Sep 6, 2006)

I'd put my money on betting that we'll need to get the S4 in order to use CC 2.0.

Now if Tivo wants to be real cool, they'll have a decent trade-in program and allow a free transfer of lifetimes for those that purchased them for the S3.

Otherwise, they risk a pretty bad backlash from the S3 owners... but enough with the negativity... we'll worry about that when the S4 is released and after we see how Tivo deals with this...


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## mlear (Dec 14, 2002)

Hrmm, this is a total bummer. Again, not necessarily a deal breaker, but if I'm forced to use my cable companies' box for PPV events and individual sports games, I'm less inclined to buy a Tivo.

Does anyone have an idea when 2.0 is slated to become standardized?

-Matt


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## CCourtney (Mar 28, 2006)

Most likely 18-24months before CC 2.0 standard is set.


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## Dan203 (Apr 17, 2000)

Not to mention that the current draft of CC2.0 *requires* a FireWire port, something that can't be added via a simple USB dongle.

Dan


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## sommerfeld (Feb 26, 2006)

an interesting (but most likely academic) question is whether the cablecard ports (which, mechanically, appear to be more or less the same form factor as PCMCIA/PC Card/cardbus slots), are wired up in such a way that they can *act* as cardbus slots as well as cable card slots.

there are cardbus firewire controllers (and USB DOCSIS modems, for that matter).


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## Dan203 (Apr 17, 2000)

I've brought up that theory myself. Unfortunately someone more knowledgeable pointed out that CableCARD does not operate using cardbus so it's highly unlikely that the slots are wired correctly for cardbus operation. 

Dan


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## classicsat (Feb 18, 2004)

tomryan said:


> Of course, what's to stop tivo (as part of their partnership with cox/comcast) from asking them (nicely of course), if the two way comm could come back over the ethernet.. (of course requiring that you have a cable modem setup from them)..
> 
> I can't see why they couldn't do that either.. of course, I highly doubt that would happen, but I can dream!


OCAP aside, anything that TiVo would have to make for the Series 3 to do universal bi-directional will have to meet the scrutiny of Cablelabs, not Comcast, Cox or whomever.

I don't think they would care to approach cable providers directy to get further features added to the S3.


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## Leo_N (Nov 13, 2003)

Dan203 said:


> Not to mention that the current draft of CC2.0 *requires* a FireWire port, something that can't be added via a simple USB dongle.
> 
> Dan


Isn't it weird that it *requires* a firewire port, you'd think they'd rather not have another digital port heading out of any box with a CC in it.


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## rrman (Mar 6, 2005)

I've never paid for PPV shows from my cable company. I've occassionally (maybe two to three times a year) have used the free on demand programming when I've gotten really desperate, but the picture quality of the on-demand stuff is pretty bad - the pictures are highly compressed, and on a 92" screen barely watchable. So, although it's nice to know I can get it when I want it, in reality, I don't (and have never) used the PPV stuff, and only very seldomly used the free on-demand programming (and that's when I'm just killing time since my SA 8300HD didn't program what it was suppossed to). So, the lack of two-way CableCard doesn't bother me. The only concern I have is the cable companies' potential use of SDV in the future.


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## Dan203 (Apr 17, 2000)

Leo_N said:


> Isn't it weird that it *requires* a firewire port, you'd think they'd rather not have another digital port heading out of any box with a CC in it.


There is an FCC mandate that requires all cable company supplied STBs have an active firewire port. And since CC2.0 is designed to be used in cable company STBs it makes since that they would require firewire in the spec.

And it's not a big deal that it's digital because it's still 5c encrypted, so content providers can block their signal from going out over firewire if they want.

Dan


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## eisenb11 (Sep 6, 2006)

Dan203 said:


> *There is an FCC mandate that requires all cable company supplied STBs have an active firewire port*. And since CC2.0 is designed to be used in *cable company STBs* it makes since that they would require firewire in the spec.
> 
> And it's not a big deal that it's digital because it's still 5c encrypted, so content providers can block their signal from going out over firewire if they want.
> 
> Dan


Actually, this logic is a bit flawed. While it is mandatory that the cable co STB have a firewire port, that does not mean that the CC must support firewire.

Firewire is an issue that will be handled within the STB. It's not a CC issue.

Since a Tivo is not supplied by the cable co, it doesn't need to comply with the firewire requirement.

However... the S3 does lack the ability for bi-directional communications so it's pretty moot anyways.

The only thing we can hope for is either:

1. Tivo offer a nice trade-in program
2. Tivo offer an upgrade program

(2) would be nice. Literally, all the would need to do is swap the mainboard out for another one and all would be set - charge us the cost for the replacement board and some labor and all is cool...


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## Leo_N (Nov 13, 2003)

Dan203 said:


> There is an FCC mandate that requires all cable company supplied STBs have an active firewire port. And since CC2.0 is designed to be used in cable company STBs it makes since that they would require firewire in the spec.
> 
> And it's not a big deal that it's digital because it's still 5c encrypted, so content providers can block their signal from going out over firewire if they want.
> 
> Dan


I'm not saying it's not true. I'm saying what is the point of firewire? It seems to have no relevance to the rest of the spec whatsoever. Why exactly would any CC2.0 device need any firewire port at all?

Again, I say it's not bad to have it, but *WHY* require it?


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## Aiken (Feb 17, 2003)

Dan203 said:


> Not to mention that the current draft of CC2.0 *requires* a FireWire port, something that can't be added via a simple USB dongle.


Er, why not? Firewire is just a wired communication medium. Granted, it'd be more than just a cable adapter, but it certainly wouldn't be impossible to put a controller on a USB dongle that could read one port and throw the data at the other. Am I missing something?


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## classicX (May 10, 2006)

CCourtney said:


> CC 2.0 will use DOCSIS based modem technology to transmit data back to the head end. After all it has to go back via Cable and CableLabs always uses DOCSIS based designs for this stuff in their specs as DOCSIS is there cable modem specification.
> 
> I would seriously doubt anyone would invest in creating an upstream DOCSIS module that would connect up to the USB in the first place. And there's no way in hell that CableLabs would approve such a device in the second place.
> 
> ...


I wasn't dreaming about it. In fact, I don't care. I was just answering the OP's question.


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## Maeglin (Sep 27, 2006)

Aiken said:


> Er, why not? Firewire is just a wired communication medium. Granted, it'd be more than just a cable adapter, but it certainly wouldn't be impossible to put a controller on a USB dongle that could read one port and throw the data at the other. Am I missing something?


Because even USB 2.0 couldn't keep up with Firewire data rates... unless I'm mistaken. Then again, if you never used it it wouldn't really matter.


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## JStanton_boston (Mar 18, 2004)

Dan203 said:


> Not to mention that the current draft of CC2.0 *requires* a FireWire port, something that can't be added via a simple USB dongle.
> 
> Dan


Firewire ports that connect to your computer via USB are certianly available.

http://www.cdw.com/shop/products/default.aspx?EDC=513590
http://www.pixela-1.com/captycable/


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## JStanton_boston (Mar 18, 2004)

Maeglin said:


> Because even USB 2.0 couldn't keep up with Firewire data rates... unless I'm mistaken. Then again, if you never used it it wouldn't really matter.


The standard IEEE-1394 (Firewire) interface is 400Mb/s. USB 2.0 is 480Mb/s.

There is an Firewire 800 standard that runs at 800Mb/s, but this uses a different, 9-pin connector and isn't in common use. I can't believe that they're going to require that on the CC2.0 devices.


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## Redux (Oct 19, 2004)

JStanton_boston said:


> The standard IEEE-1394 (Firewire) interface is 400Mb/s. USB 2.0 is 480Mb/s.


Real world, firewire can do sustained streaming like video while USB stutters. There are ways to get around that, buffers and such, but it's an inherent advantage of firewire.


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## lgerbarg (Jun 26, 2000)

classicX said:


> It's fact - the S3 doesn't have the required hardware.
> 
> Whether there may be some sort of USB add-on that could do it, only time will tell.


That is wrong. There is no discrete DOCSIS modem. There is a fairly large Xilinx FPGA that can be used for a DOCSIS modem. Xilinx even sells an DOCSIS core for it.

The question is how much of the FPGA is used for anything right now, and if there is enough space left for a modem. Given the incremental costs of adding a slightly larger FPGA compared to the other things they put in the system speculatively (MPEG4, eSATA PHYs, etc) it seems likely to me that they have enough space there.

I can pretty much guarantee TiVo will not promise a feature like that until they are confident they can implement and certify it though. It may be that they just will not be able to do it, but I suspect they will attempt to. It is in their best interest to avoid having to roll their HW platform if they can avoid it.


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## Dan203 (Apr 17, 2000)

JStanton_boston said:


> Firewire ports that connect to your computer via USB are certianly available.
> 
> http://www.cdw.com/shop/products/default.aspx?EDC=513590
> http://www.pixela-1.com/captycable/


The first one is just a combo hub, it doesn't actually translate from USB to FireWire. The second one however does sound like it actually converts from FireWire to USB. Although, as mentioned above, the realworld throughput of FireWire is better then USB 2.0, so I'd be surprised if it worked without dropping frames.

Dan


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## MichaelK (Jan 10, 2002)

Krellion said:


> The TiVo would require the hardware that's needed to transmit data back to the cable company, which it most likely doesn't have.


someone posted that one of the chips in the S3 MIGHT be firmware upgradeable to become a doscis modem.

(off to search and try to find the post...)

If that could some how occur, then the only problem would be the lack of firewire ports....


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## MichaelK (Jan 10, 2002)

CCourtney said:


> CC 2.0 will use DOCSIS based modem technology to transmit data back to the head end. After all it has to go back via Cable and CableLabs always uses DOCSIS based designs for this stuff in their specs as DOCSIS is there cable modem specification.
> 
> I would seriously doubt anyone would invest in creating an upstream DOCSIS module that would connect up to the USB in the first place. And there's no way in hell that CableLabs would approve such a device in the second place.
> 
> ...


stupid question- I guess- BUT i just got to thinking-

like every docsis modem I've ever seen has a usb port for connecting to a pc- so from a technology standpoint why couldn't you do an external docsis modem by the tivo's usb port? Is that USB communication not secure?


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## MichaelK (Jan 10, 2002)

Dan203 said:


> Not to mention that the current draft of CC2.0 *requires* a FireWire port, something that can't be added via a simple USB dongle.
> 
> Dan


and anothe stuipid question- is there no such thing as a firewire-> usb2.0 dongle?


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## Dan203 (Apr 17, 2000)

MichaelK said:


> and anothe stuipid question- is there no such thing as a firewire-> usb2.0 dongle?


Actually apparently there is. Check out the second link in this post....

http://www.tivocommunity.com/tivo-vb/showthread.php?p=4428909&&#post4428909

Dan


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## classicsat (Feb 18, 2004)

lgerbarg said:


> The question is how much of the FPGA is used for anything right now, and if there is enough space left for a modem. Given the incremental costs of adding a slightly larger FPGA compared to the other things they put in the system speculatively (MPEG4, eSATA PHYs, etc) it seems likely to me that they have enough space there.


That is for a future revision of the S3 though.

How Bi-Directional can apply to current hardware is what is in discussion here.



MichaelK said:


> someone posted that one of the chips in the S3 MIGHT be firmware upgradeable to become a doscis modem.
> 
> (off to search and try to find the post...)
> 
> If that could some how occur, then the only problem would be the lack of firewire ports....


Actually, it would be the lack of an uplink modem/modulator, if it isn't buried in the matrix can.


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## MichaelK (Jan 10, 2002)

(I should have read the whole thread before I posted all that-LOL)

isn't igerbarg saying that the FPGA could be reprogrammed to provide that?

Or do you need to get teh docsis modem AND a modulator?


(and I think his point is that maybe they already put a large enough fpga in the thing so that either it already contains the code or is ready to be flashed to include it without the need for any addtional hardware?)


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## CCourtney (Mar 28, 2006)

MichaelK said:


> stupid question- I guess- BUT i just got to thinking-
> 
> like every docsis modem I've ever seen has a usb port for connecting to a pc- so from a technology standpoint why couldn't you do an external docsis modem by the tivo's usb port? Is that USB communication not secure?


Techinically it would be possible to feed the upstream information back up in this maner. This is not as simple as slapping a DOCSIS modem on the USB port BTW.

Price considerations, System complexity of CC implementation, CableLabs track record shows they won't certify open systems (and this would be open an system), etc. all lead to this being highly improbable.

More likely you'd see a 2nd generation S3 box with the upgraded HW, and by the time CC 2.0 comes out the pricing of these boxes will be significantly lower than what they are today.

CCourtney


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## MichaelK (Jan 10, 2002)

CCourtney said:


> Techinically it would be possible to feed the upstream information back up in this maner. This is not as simple as slapping a DOCSIS modem on the USB port BTW.
> 
> Price considerations, System complexity of CC implementation, CableLabs track record shows they won't certify open systems (and this would be open an system), etc. all lead to this being highly improbable.
> 
> ...


myself- i think there will be a seris 3.5 with 2-way cc if it ever comes to be.

But I was just wondering about the technology.

By "open system" do you mean the communication over USB is not secure? (sorry if i'm thick- just trying to learn)


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## JDguy (Jan 16, 2006)

mbhuff said:


> What's more version 2.0 of CC as it stands requires OCAP.





CCourtney said:


> CC 2.0 will use DOCSIS based modem technology to transmit data back to the head end.





CCourtney said:


> Most likely 18-24months before CC 2.0 standard is set.





Dan203 said:


> Not to mention that the current draft of CC2.0 requires a FireWire port,


It's all hogwash... The best response was this one:



eisenb11 said:


> Actually, this logic is a bit flawed. ...
> Firewire is an issue that will be handled within the STB. It's not a CC issue.


The very premise is flawed starting with this quote:


mlear said:


> Does the S3 support CableCARD 2.0?
> The CableCARD 2.0 specification has not been finalized at this time, so it is not possible to give a final answer. However, the current CC 2.0 proposal requires hardware the S3 does not have. Therefore, the S3, as it stands today, would not be able to support bidirectional communication for CC 2.0 features such as OnDemand or Switched Digital Video. If a 2.0 card is inserted it should fall back to 1.0 with Multi-Stream. .


As a refresher, everyone please repeat after me:
"All CableCARDs are 2-way." 
"The CableCARDS you have today are two-way"
"The lack of two-way functions in a receiver prevents that receiver from accessing two-way services, not the CableCARD"
"CableCARD-2.0 specs added multistream functionality, two-way functionality was already there."
"CableCARD-2.0 specs have been published since March 31, 2005"
"To support two-way services, a receiver must follow the OpenCable Host-2.0 specifications." 
"OpenCable Host-2.0 specs have been published since 8/31/2004"
"Some two-way OpenCable Hosts use a single stream CableCARD, others will use a mulit-stream CableCARD"


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## Maeglin (Sep 27, 2006)

And who's the confused one here? TiVo states very clearly that 2.0 cards aren't supported (at least the 2-way nature of them), but they do support multistream cards. If the local Comcast CSR that I talked to a few days ago is correct that they have multistream cards (this was after he checked with his supervisor), and the card actually works that way when it's installed, then would you like catsup or mayo with those words?

Yes, I will be posting about it in the official Comcast thread once the installer is done.


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## Stormspace (Apr 13, 2004)

HiDefGator said:


> It's unlikely Tivo would bother making a USB add-on for the S3. It would be far more logical to put the effort into the new S4 box instead.


I agree, if TiVo was interested in add-on boxes they'd have been producing them for other things in the past. They barely made the USB ports support wireless adapters, they certainly won't be doing anything else just like they haven't done anything with e-Sata.


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## CCourtney (Mar 28, 2006)

MichaelK said:


> myself- i think there will be a seris 3.5 with 2-way cc if it ever comes to be.
> 
> But I was just wondering about the technology.
> 
> By "open system" do you mean the communication over USB is not secure? (sorry if i'm thick- just trying to learn)


What I mean by open system, is a system where it requires the interaction of two or more items that are sold seperately to complete functionality (in this case CC functionality would be split between S3 and the USB Adaptor) and then items are sold separetly and put together to complete that functionality.

CableLabs will only test closed systems (you can have two physical seperate components such as a PCI Cable Modem Card + PC but they're Certified as a System and would have to be sold as a System, hence closed system to have the CableLabs certification.)

CCourtney


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## MichaelK (Jan 10, 2002)

CCourtney said:


> What I mean by open system, is a system where it requires the interaction of two or more items that are sold seperately to complete functionality (in this case CC functionality would be split between S3 and the USB Adaptor) and then items are sold separetly and put together to complete that functionality.
> 
> CableLabs will only test closed systems (you can have two physical seperate components such as a PCI Cable Modem Card + PC but they're Certified as a System and would have to be sold as a System, hence closed system to have the CableLabs certification.)
> 
> CCourtney


thanks for explaining.

So could tivo (in theory- as I said above- I think 3.5 is more likely) submit a series3 with an 'offical' tivo branded usb docsis modem and get that approved as a "system"?


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## lgerbarg (Jun 26, 2000)

classicsat said:


> That is for a future revision of the S3 though.
> 
> How Bi-Directional can apply to current hardware is what is in discussion here.


I do not think you understand what an FPGA is. It is a reprogrammable logic chip. In fact, some FPGAs actually have to be loaded every time they are initialized, so reprogramming them is as simple as changing a file in the boot image. The FPGA is there is the current hardware. Assuming the cable feed is wired to one of the inputs on the FPGA a DOCSIS modem can be loaded onto the part in current TiVos. Again, the question is if the FPGA is currently utilized to such an extent that there is no room for a DOCSIS softcore.

Since no one has actually traced the board inputs, or figured out what the FPGA is used for, it is entirely possible the current hardware platform could be made compatible with the transmission requirements for CC 2.0.

Again, I in no way want to make people think it is likely that will happen, or that they should base their purchase on it. But if I was TiVo, and by making a change to one trace on the motherboard, and spending $2-3 on a slightly larger FPGA than what I needed to make the S3 function I might save myself the hassle of reving the hardware platform, flushing channel inventories, and annoying my current customers I would certainly do it. At least I would do it before wasting money on an eSATA port and MPEG4 chip that I was not using at launch ;-) So I think that is what they probably did.


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## eisenb11 (Sep 6, 2006)

Igerbarg,

The FPGA may not be the limiting issue. It really depends on what they're using it for (and only Tivo knows). It's quite possible that FPGA space won't be important.

Maybe, in theory, the coupling of a CC2.0 + S2 + USB DOCSIS modem will take care of the problem.

Honestly, though, I'm not counting on it... I have a feeling we'll be buying new boxes when the S4 is released unless Tivo feels like showing us a little mercy on a trade-in...


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## lgerbarg (Jun 26, 2000)

eisenb11 said:


> Igerbarg,
> 
> The FPGA may not be the limiting issue. It really depends on what they're using it for (and only Tivo knows). It's quite possible that FPGA space won't be important.
> 
> ...


I completely understand that. The point I am making is that it is entirely possible the current box has sufficient hardware for bidirectional cable services. Whether or not it will work out for early adopters is always a gamble. The take home point is that the S3 is a very impressive piece of hardware, and a lot more flexible than people seem to think.


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## classicsat (Feb 18, 2004)

MichaelK said:


> (I should have read the whole thread before I posted all that-LOL)
> 
> isn't igerbarg saying that the FPGA could be reprogrammed to provide that?
> 
> ...


You can program the FPGA all you want (if it can be field programmed by a downloadable update). The missing piece of hardware is the device or circuitry to put the signal coming from the FPGA onto the coax.

You can't program hardware into software.


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## classicsat (Feb 18, 2004)

lgerbarg said:


> I do not think you understand what an FPGA is. It is a reprogrammable logic chip. In fact, some FPGAs actually have to be loaded every time they are initialized, so reprogramming them is as simple as changing a file in the boot image. The FPGA is there is the current hardware. Assuming the cable feed is wired to one of the inputs on the FPGA a DOCSIS modem can be loaded onto the part in current TiVos. Again, the question is if the FPGA is currently utilized to such an extent that there is no room for a DOCSIS softcore.


I know what an FPGA is.

I also know what it isn't, and it doesn't directly connect to the coax line. A coax interface of some sort has to exist between the FPGA
and the coax line, and more than likely, the current Series 3 hardware lacks such hardware, so programming an FPGA does no good if the hardware to take advantage of that code is not present.


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## sjcbulldog (Jul 13, 2004)

Actually, unless the FPGA is pin limited, it is very likely that the connection exists. When building a system like this, if an FPGA is part of the system, looking ahead to bug fixes or expansions generally drives the design to route those signals that might be of interest to the FPGA. The FPGA is the hardware so by adding a few traces to the board you increase the possibilities for the future a great deal.

I have no specific information on what TiVo actually did, but if the pins existed on the FPGA it is likely that appropiate signals were routed to the FPGA.

However, you could be refering to what ever drivers are required to drive the output signal onto the coax. I do not know what type of drivers would be required to drive the signal generated by the FPGA back onto the coax.

Sjcbulldog


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## eisenb11 (Sep 6, 2006)

lgerbarg said:


> I completely understand that. The point I am making is *that it is entirely possible the current box has sufficient hardware for bidirectional cable services*. Whether or not it will work out for early adopters is always a gamble. The take home point is that the S3 is a very impressive piece of hardware, and a lot more flexible than people seem to think.


On the highlighted point... the hardware is *not* there.

At the least we'd need a USB DOCSIS modem. They can reprogram the FPGA all they want, but without DOCSIS hardware (not present currently) it's not going to do us any good...


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## MichaelK (Jan 10, 2002)

eisenb11 said:


> On the highlighted point... the hardware is *not* there.
> 
> At the least we'd need a USB DOCSIS modem. They can reprogram the FPGA all they want, but without DOCSIS hardware (not present currently) it's not going to do us any good...


man you guys are confusing the spit out of me- LOL. Everyone posting here seems way more knowledgable than I- but here's my ignorant understanding-

isn't lgerbarg saying that the FPGA could be flashed to become a DOCSIS modem?

Than classicsat is saying that you can make that chip into a DOCSIS modem all you want but if it isn't connected to a cable coax line then it just doesn't matter.

Then sjcbulldog is saying it's possible that they did make the correct physical connections.

So if I'm understanding correctly IF:
1) the FPGA has enough room left over 
2) and it has a physical connection to the cable coax

then yes the current S3 hardware could be made to have a working docsis modem for bidirectional communication.

but that doesn't do anything about the lack of firewire port....


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## Maeglin (Sep 27, 2006)

If there's a modulator capable of sending DOCSIS signals back over the coax, then who knows... I could be wrong (since I know little about the way they work), but it doesn't seem like reprogramming an FPGA would provide that.

As for the firewire port, there may be a mention of it in the specification, and that is likely driven by FCC requirements for cable STBs, but the whole idea of a CableCARD is to divorce the decryption and conditional access in a cable STB from the rest of it so that's rather contradictory from that standpoint. So is the idea of the cable provider loading their own operating system onto whatever the card is plugged into.

Whether the port should be in a CableCARD host should be governed by why it is needed there. Is it actually going to serve a useful purpose in a DVR, or will it be like the appendix in a human body (does nothing, really, but if it breaks down it makes itself known)? Last I saw, the FCC doesn't even specify a purpose for it in cable STBs... they just want it to be there.


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## MichaelK (Jan 10, 2002)

Maeglin said:


> If there's a modulator capable of sending DOCSIS signals back over the coax, then who knows... I could be wrong (since I know little about the way they work), but it doesn't seem like reprogramming an FPGA would provide that.
> ....


sorry I'm being totally dense-

some seem to be saying a docsis modem (as the fpga can be programmed to become) is the modulator (as long as it's connected to the coax physically)- but others seem to be saying a docsis chip and a modulator chip are 2 differnt things.

Can someone clarify which it is?


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## MichaelK (Jan 10, 2002)

the link posted early on to the xlinx docsis core here:
http://www.xilinx.com/xlnx/xebiz/de...BModulator&sGlobalNavPick=&sSecondaryNavPick=

calls itself a


> J.83 Universal Modulator Annex B
> Xilinx IP Core


it's listed in the 'modulation demodulation' section of their product list.

and it says


> The DOCSIS ITU J.83 Annex B Modulator core offers a programmable digital baseband modulator for cable modem termination systems (CMTS) in North America





> ITU-T J.83 Annex B Compliant baseband transmitter for Cable Modem Termination Systems (CMTS)


so itsn't the core being sold the docsis modem and the modulator?

So then the limiting facotr would be if it is in fact physically connected to the coax?

(also there's no reason for firewire but that's what the current cablelabs spec says so tivo would need to have it to get certified- doesn't matter if it makes sense or not)


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## MichaelK (Jan 10, 2002)

I looked at the other place and found the boot console text and here seems to be the bit abouit the fpga:



> ....
> boardId 0x00102489 : loading fpga for P1.5 or later
> Starting programming...
> done!
> ...


anyone in the know glean anything from that as to what the fpga might be doing?


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## besposito (Jan 30, 2005)

HiDefGator said:


> It's unlikely Tivo would bother making a USB add-on for the S3. It would be far more logical to put the effort into the new S4 box instead.


Where's the forum on the new S4? Where's the FAQ? Whens it coming out?...now that I have an S3 the anticpation rush is gone...so I gotta have my fix for the next one...i am sure it will be out by next summer


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## Maeglin (Sep 27, 2006)

besposito said:


> Where's the forum on the new S4? Where's the FAQ? Whens it coming out?...now that I have an S3 the anticpation rush is gone...so I gotta have my fix for the next one...i am sure it will be out by next summer


We need Ritalin in here, stat!


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## ashu (Nov 8, 2002)

Whoa. My head is spinning.

I think I can summarize this thread into "Go forth and buy an S3 TiVo". OK. Will do.

Jokes aside, some good discussion here, but ALL this seems to be raised repeatedly every few days in a new thread!


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## lgerbarg (Jun 26, 2000)

MichaelK said:


> sorry I'm being totally dense-
> 
> some seem to be saying a docsis modem (as the fpga can be programmed to become) is the modulator (as long as it's connected to the coax physically)- but others seem to be saying a docsis chip and a modulator chip are 2 differnt things.
> 
> Can someone clarify which it is?


People are confusing two things. And I have not been entirely clear. There is usually a distinction between the logical part of communications interface and the physical part. On an ethernet connection these are called the MAC and the PHY, I am not sure the exact terminology in this case.

You need a core to do all the DOCSIS protocol work, etc. The FPGA can provide that. You also need the equivalent of a PHY, which converts the raw cable signal (which may be at voltages that the FPGA chip cannot directly handle) into an appropriate raw signal for the FPGA to handle. On some interfaces the PHYs are very complex (USB and Firewire PHYs sometimes do Differential encodings, etc). Other ones are basically glorified resistors that just do a little voltage conversion.

When we talk about the coax being rigged into the FPGA we are really talking about the coax PHY having a line routed through the FPGA. We implicitly know The S3 has some sort of PHY so it can read the datastream it needs in order to get the data it hands to the CC1 device in order to get programming info. Conceivably that PHY might not have hardware that does the reverse conversion, in which case nothing you can do on the FPGA will help. But the PHY is cheap part (single wire, non-differential, etc), and it probably costs basically the same for one capable of bidi as single direction.


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## MichaelK (Jan 10, 2002)

thanks for explaining.


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## eisenb11 (Sep 6, 2006)

MichaelK said:


> man you guys are confusing the spit out of me- LOL. Everyone posting here seems way more knowledgable than I- but here's my ignorant understanding-
> 
> isn't lgerbarg saying that the FPGA could be flashed to become a DOCSIS modem?
> 
> ...


In short, the FPGA is a programmable chip. Think of it as a CPU with some built-in software that can be reprogrammed.

In order to be bi-directional we need a DOCSIS modem.

The FPGA can be reprogrammed to support a DOCSIS modem, but if the hardware isn't there you can't accomplish the goal.

In terms of a computer think of it as a PC without a network card. You can install a driver for the network card, but without the card that driver isn't going to do anything.

The million dollar question is whether or not the physical hardware for DOCSIS communications is present in the S3. It is believed that the answer to this is "no, there is no modulator".

Without the hardware the FPGA doesn't matter (in this regard). If the hardware is there, however, and just inactive/unsupported reprogramming the FPGA could potentially take care of this problem.

If we assume that the hardware isn't there, the problem could potentially be solved via a USB DOCSIS modem... but it is unlikely that Tivo would sell such an upgrade and would, rather, insist we purchase a S4.


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## MichaelK (Jan 10, 2002)

so modulater=phy?


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## sjcbulldog (Jul 13, 2004)

eisenb11 said:


> In short, the FPGA is a programmable chip. Think of it as a CPU with some built-in software that can be reprogrammed.
> 
> In order to be bi-directional we need a DOCSIS modem.
> 
> ...


Without knowing specifically which FPGA is used as well as what is required to drive the coax this is all speculation. Many FPGAs today target the communications market and include various phy's on the silicon. If this FPGA supports the correct phy and Tivo connected it to the cable then there is hope.

My guess would be it is a cost tradeoff. If the cost of a slightly larger FPGA with the appropraite PHY for driving the cable was within reason, they would have used it and left the door open for the future. However, if the costs were significant ($10 would be significant on this type of device most likely) then they would have take the less expensive route.

They can take the basic existing S3 design, worst case spin the board, and create and S4 with cable card 2 support. The costs for them will be relatively minimal on the board spin, and will basically involve the design work within the FPGA and software to support cable card 2.0.

Just my $0.02 worth
Sjcbulldog


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## MichaelK (Jan 10, 2002)

sjcbulldog said:


> Without knowing specifically which FPGA is used as well as what is required to drive the coax this is all speculation. Many FPGAs today target the communications market and include various phy's on the silicon. If this FPGA supports the correct phy and Tivo connected it to the cable then there is hope.
> 
> My guess would be it is a cost tradeoff. If the cost of a slightly larger FPGA with the appropraite PHY for driving the cable was within reason, they would have used it and left the door open for the future. However, if the costs were significant ($10 would be significant on this type of device most likely) then they would have take the less expensive route.
> 
> ...


how can we figure out what FPGA is used? is it an obvious chip with a part number on the motehrboard?


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## lgerbarg (Jun 26, 2000)

eisenb11 said:


> In terms of a computer think of it as a PC without a network card. You can install a driver for the network card, but without the card that driver isn't going to do anything.


That analogy is totally incorrect. The correct thing is to think of it as a computer that has an ethernet plug, but no ethernet chip. Once you load the driver the FPGA *becomes* the chip. Of course, the caveat is that the pins on the plug have to be wired into the pins on the FPGA, which is what we are not sure about.

In other words, the FPGA does not need a DOCSIS modem. Once you load the DOCSIS softcore the FPGA *is* a DOCSIS modem. That is the whole point of this dicussion.

From the public design sheet it appears the only external pieces needed are clock generation (the FPGA definitely has clocks wired into it), and a D/A of some sort (a rather simple, though offboard PHY), of which there are dozens (both integrated and discrete) are on the board. All the building blocks appear to be there, the question is if they are wired up in the right way, and if there is enough room on the FPGA.


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## lgerbarg (Jun 26, 2000)

MichaelK said:


> how can we figure out what FPGA is used? is it an obvious chip with a part number on the motehrboard?


It is the Xilinx Spartan 3 XC3S200. It is located on the motherboard under the CableCard slots. I can't seem to load Megazone's images right now, or I would link it.

The Spartan 3 does not actually get flashed so to speak. It actually has to have its programming loaded onto it every time it is turned on. You can connect a flash chip to it which it will automatically load its programming off of. But TiVo would probably only do that if the FPGA was needed as part of the devices bootstrap (say if it was implementing their SATA controller).

It does not appear to be needed in the boot path and I did not see an appropriate PROM near it, so it seems likely that they are programming it every time the TiVo loads its drivers. Conceivably there might be a firmware file for it somewhere in the TiVos ext2 partition. Failing that the firmware is probably statically compiled into their kernel driver. So if someone really wanted to they could probably figure out the FPGAs utilization by looking through the TiVo's HD image.


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## JDguy (Jan 16, 2006)

mlear said:


> I read in the FAQ the section that states:
> 
> *Does the S3 support CableCARD 2.0?*
> _The CableCARD 2.0 specification has not been finalized at this time, so it is not possible to give a final answer. However, the current CC 2.0 proposal requires hardware the S3 does not have. Therefore, the S3, as it stands today, would not be able to support bidirectional communication for CC 2.0 features such as OnDemand or Switched Digital Video. If a 2.0 card is inserted it should fall back to 1.0 with Multi-Stream._
> ...


Dragging up this old thread...

There seems to be some new information on this topic posted on the CableLabs web site. Perhaps it will clear up some of the confusion that seems to persist on this topic. CableCARD Primer.
http://www.opencable.com/primer/cablecard_primer.html


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## dt_dc (Jul 31, 2003)

JDguy said:


> Perhaps it will clear up some of the confusion that seems to persist on this topic. CableCARD Primer.
> http://www.opencable.com/primer/cablecard_primer.html


Doubtfull ...

However, yes, that is a pretty good primer ... thanks for the link.


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