C&W/NTL/Telewest Box Revival

Short introduction before I get to the meat of this one. Essentially what I'm trying to do is explore and document various forms of TV reception gear from the last 40 years or so as I feel it's getting lost to time and isn't quite as respected in historical terms as, say, 405 line TVs and such. In doing so I want to take plenty of photos and screenshots but, in aid of doing that as extensively as I can and to show what it was actually like to use that gear, I'd like to actually get this stuff working as-was and to document how others can do the same with their favourite nostalgic equipment.

The general goal is that when these services are discontinued and the boxes no longer capable of receiving anything, they may still be used independently of their original networks to demonstrate or relive the experience of watching TV from what will very soon be the past.

Thus far I'm able to "broadcast" to the following types of receivers:

625-line PAL (standard modulators)
Sky analogue (thanks to the excellent hacktv project)
BSB (albeit with some visual issues, but thanks again to hacktv)
ONdigital (thanks to gnuradio and a bit of bash scripting)

Now, two of the obvious remaining (modern) mainstream platforms are Sky Digital and the various DVB-C cable networks such as Cable & Wireless, Telewest, NTL, and most recently (albeit a continuation of the others) Virgin.

Sky Digital is a bit tricky, it has expectations/limitations on its signal parameters which make it more difficult to work with (although it's not impossible). Which leaves me looking at cable and brings us to what I'm looking for.

I don't know a great deal about these cable networks, I've never had cable, but I'm aware that they use DVB-C for transmitting video and some video-related data. I'm also aware that there are a number of pre-set frequencies (which vary by physical location in the country) which handle different stuff, one of which seems to be the default DVB-C channel from which I presume the box will put the NIT (Network Information Table which describes what's available for the box to tune to).

What I don't yet know, and what would be quite important to know in order to get these boxes doing something again, is the following:

How much of the network architecture, beyond the default DVB-C channel, does the box need to function to the extent that the viewer may watch a TV channel? For this project, being able to view and browse TV channels is the goal, whilst it would be nice to be able to simulate other elements such as cable internet, that's currently beyond my scope (and probably capabilities).

Is the EPG stored locally or is it broadcast as data with the TV channels? Given these boxes refuse to even boot to a state where you can browse the off-air (and in fact totally absent) channels, I'm unsure whether the firmware itself contains all of the necessary software and assets to operate standalone.

Is there anything highly specific to these cable networks (beyond standard DVB expectations) which is required? In particular, special parameters or data elements which would not normally be required by a DVB-C network, such as a stream which contains important data, without which the box will refuse to work?

If anybody has any multiplex dumps of the default frequency channel(s), I suspect that would be quite helpful. Well, provided they're not encrypted. But if it's possible to pull the necessary data streams from a dump, it would likely be possible to recreate a replica which will function in its absence. To clarify, this would be a dump of the full 40Mbps mux, as opposed to a recording of a channel that lives in it, so it would contain all of the data you don't typically need to know exists as a normal viewer.

I have a vague understanding of how some of this works (having needed to know some of it for ONdigital) and I'm able to transmit a signal that the engineering menu picks up as a suitable DVB-C multiplex, but as yet I'm unable to get any box to boot normally to attempt to view channels. It's slow progress, but it's progress.

Cheers for reading my less-short-than-intended post and for any insight anybody can give. In the meantime I'll keep poking stuff and will report back any progress.



(Disclaimer note, just in case: This project does not involve any connection to Virgin's networks and the purpose is to be able to transmit content to a disused cable receiver for the sake of preserving functionality of those no longer supported. It will involve no modification of receivers, per the historical preservation goal, and is not connected to any attempts to pirate content or otherwise bypass security restrictions. Unless doing so will enable me to time travel.)

https://www.digitalbitrate.com/dtv.php?mux=C029&liste=2&live=209&lang=en might be worth a look - it has Virgin Media mux information - and C70 looks like it might have some STB related stuff (Whether that is firmware update or data for day-to-day operational use - I've no idea)

I don't know if VM use standard EIT for their EPG (as Freeview SD uses), or a more proprietary EPG like Freesat, Freeview HD and Sky.

Annoyingly - connecting any non-Virgin receiver (or similar) to a VM cable point is in breach of their Ts & Cs - though I guess if you aren't a subscriber that may not be an issue (and you could mux dump a mux carrying FTA services to check?)

Thanks for that, never know what info might come in handy.

Thankfully my ONdigital box didn't much care about an EIT, so I was able to omit that and still get the thing to function correctly. In the future I'd like to add that, but it's all extra stuff to have to dig around in and learn, and ideally if I can get by with just the basics for now, that'd make getting to a point where it can be added much easier. Hopefully (although I'm not super confident) the cable boxes can be persuaded to go without it until I can get the basics functional (enough to get it to boot normally).

Unfortunately I'm unable to access a Virgin feed myself, so even aside from Ts & Cs I don't have that option.

I also don't know how much the system has changed over the years and how compatible the current setup is with older boxes, although much like Sky Digital boxes it seems like most of them have been updated over the years anyway, given the previous owners wouldn't have had much choice in the matter. I gather they used to use 64QAM instead of the current 256QAM, but that's about the only difference I know of so far, and that alone wouldn't be too much of an issue to fix if I run into any older boxes.

My technical knowledge here will be absolutely useless to you, but what a fascinating and, arguably, vital project. Reminds me of format obsolescence, in a way, although I know this is a slightly different situation.

Are you planning to/have you written about this anywhere, blog perhaps?

Yeah, that's the thing, unlike the retro computing scene and to some extent vintage TV collectors who are interested in TV sets from the first half of the 20th century, these "modern" boxes don't get much attention despite now being 20+ years old and much more quickly obsolete. I'm not keen on that as they're just as culturally relevant (albeit to a younger generation) as a 405 line TV or a ZX Spectrum.

As you say, physical media formats too, they're (somewhat) preserved by different groups of people, those dumping computer/game ROMs, imaging floppy and optical discs, capturing video tapes and extracting teletext, all that stuff. Broadcast TV, in all its forms, is essentially that but via a more ephemeral medium. It's all just a big pile of ways to deliver content to consumers, even if you can't hold some of it in your hands.

Emulation is big too, and important for when all this hardware becomes too rare, too expensive, and too difficult to maintain. As far as I know, nobody's emulated any of these TV boxes yet. I'd love to see that, but my technical knowledge doesn't get me quite that far at the moment. There could perhaps be some concern over big pay TV companies not taking kindly to such practices too, although I'm sure for the most part it's simply a lack of interest in emulating such a mundane (and quite hardware-focussed) genre of equipment.

But yes, I am planning to document my efforts to produce these TV signals compatible with old boxes. I have a website (Set Top Boxing) but it's currently in the middle of a refresh as there are some misleading links which go nowhere due to my excessive optimism in how quickly I could populate the site with all the info, amongst some number of other deficiencies. I have a work in progress site designed to replace it, which will be available at the same URL, but in the meantime the existing site should give you an idea of what I'm trying to do.

I'm improving and expanding my photography and I expect to include more photos and screenshots, which is part of why I want to be able to show these boxes operating as they did 20+ years ago, naturally this requires being able to operate them despite their services being potentially no longer compatible or simply no longer active. In addition to that, I'll be documenting how I did it for each service so that others can use the same tools to rig up their own boxes and do the same. There are some unfortunately fairly technical aspects to some of it, but as it makes it easier for me to simplify the process as much as possible for my own convenience, hopefully that streamlining will be passed on in those articles. There's some somewhat expensive kit to buy too, which I wish wasn't the case, but this is a pretty niche thing which requires pretty niche equipment. I'd like to make it as easy as possible though, even if I can't make it cheap(er).


Edit: Couple of pictures from my journey so far. Not necessarily that interesting as I've been focussing on getting it to all work before taking a lot of pictures, but perhaps a little inspirational nonetheless...


Radix Delta 2002 analogue "Sky" box (PAL FM satellite) showing "Sky One"
Actually a more modern box than the channel it's showing would suggest, and technically not possible because that box isn't a VideoCrypt decoder, but it's become my trusty PAL FM receiver of choice for technical testing.


Philips STU902 D-MAC BSB box showing "The Movie Channel" (has some visual corruption)


Pace DTR735PP ITV Digital box showing a channel list after a scan of my synthesised "ONdigital" transmission

Images of more relevance to the original post:


Pace Di4000-N NTL box, engineering mode, DVB demodulation status, with no signal


Pace Di4000-N NTL box, engineering mode, DVB demodulation status, with synthesised 256QAM DVB-C signal

It's a start, but I think the box is expecting a little more from the signal, or perhaps more signals in addition, as it sits showing "nit" if booted normally. Given I'm using a fake ONdigital NIT with no service-specific data in it, that's not terribly surprising. But it's a move in the right direction at least.

Edit:


Pace Di2000 (old Telewest logo box, Virgin logo firmware) flicks back and forth between having a lock and not having a lock. Possible bitrate issue? The tools which generate these DVB streams aren't super-duper reliable when it comes to getting the data rates precisely correct. (Edit: Oops, I may have forgotten to recalculate the bitrate for 256QAM, I was using the numbers I calculated for 64QAM... although that didn't seem to fix it.)

Edit again: Managed to get the signal to appear stable according to the Di2000, which is a start. It attempts to acquire a NIT but doesn't find one (or at least doesn't find one it likes).

Edit 2: Earlier I referred to being unsure that the box firmware contained the whole UI and suggested that it's possible that it's downloaded from the feed. This appears, at least in some cases, not to be true. I discovered that a C&W branded (but upgraded to NTL firmware) Pace DiTV1000 will in fact boot to a point where the EPG can be used (although it doesn't do much as there's no data to populate it with). Given that, I feel more confident that the firmware does in fact contain the entire EPG, it just doesn't bother booting that far if there's nothing to fill it with.

Interesting! Not sure when I'll be able to do it, but I will try and get a mux-dump of the "home" DVB-C multiplex when I next see my parents (ex-NTL Stafford network area: Frequency: 826.250MHz - S/R: 6.887 - NID: 00015). They used to have cable and the connection to the network was seemingly never disconnected when they left a few years ago.

Some of the stuff on the network is actually unencrypted (The main five channels in SD, plus a couple of others and some Virgin Media static info screen channels), but pretty much everything is MPEG4 these days so you'll have to generate your own multiplexes containing MPEG2 for the old boxes like you have otherwise for your OnDigital ones etc.

The transmissions do have standard EIT schedule data transmitted (see: https://digitalbitrate.com/dtv.php?mux=C078&pid=2703&live=209&sec=0&lang=en ) but only a limited amount. I've had a look at the code of TVHeadend, which has an EPG grabber for Virgin Media cable. It looks like the full EPG is EIT data but all on a single PID - 700, I guess a little like Freesat but without the Huffman encoding. Presumably this is on the home transponder.

Here's some analysis of the current home transponder (the network here is one of the Liverpool ones I think) - https://digitalbitrate.com/dtv.php?mux=C070&liste=1&live=209&lang=en

PID 700 with the EPG is probably hidden in there somewhere. I will get a mux-dump when I next have a chance

If you could that'd be super useful, cheers! It may not necessarily require all of the data in order to get the box to do its thing, but I suspect it's looking for quite specific stuff in quite specific places (as it's only designed to work with NTL/Virgin, so they'd be in full control of the infrastructure), so getting an idea of what the real thing looks like seems like it'd be fairly important.

I'll take a look at the TVHeadend stuff, thanks for the tip, it might give me some idea of the format of the EITs and how standard it is. I still don't know quite how to get the box to accept the mux I'm transmitting so I may not be able to test if what I give it is working properly, but it all helps. When enough right pieces are there, I'm hoping the rest should "just work" as long as it's fairly standard DVB stuff. Could be handy to know that PID too, if things do have to be in precisely the right place, to match some specifically hardcoded firmware, that's all good info.

Having said that, I wonder if there's any region/network-specific IDs and stuff which have to match the box. As I understand it you can't just pick up one of these boxes and take it anywhere you like, but I don't know if that's a measure enforced by the back end, or the box, or the card. I should probably look at these boxes and figure out where they came from, just in case.

Since I'm here, a selection of screenshots of the DiTV1000 that does boot to the EPG without a feed, for those of a nostalgic disposition:









The version number is "P1.Build 53.25h.CR1", so it's a classic, effectively a slightly updated version of the initial turn of the century EPG software. The build date is 17 April 2003, so as far as I can tell it must've been a London area box which was never updated to CR2?

Edit: Forgot to mention, you'll note the clock is still roughly correct. It's some minutes out, but it's managed to retain the correct date and more or less the correct time. Impressive, really, several other boxes seem to have managed the same. As I don't know which regions these boxes came from or when they were last used I'm not sure how long they've been sitting around, but I've had them for a while myself.

Progress report: Switched to DiTV1000 as I thought the ability to get into the EPG would probably help test for the presence of a valid NIT. After reconfiguring everything for 64QAM and setting the network ID correctly in my NIT (the one adapted from my ONdigital tests)...




As you can see, no video (or audio) yet, currently unsure why, may be an encoding issue, may be that the streams need different IDs, or the streams need different bitrates, or I've buggered something up, dunno, but the channel numbers (albeit incorrect ones for NTL as a result of a quick copy/paste job from a previous version of my ONdigital NIT) and channel names do display and channel hopping works.

Nothing in the EPG yet as I'm not sending an EIT, but that's on the todo list.

Edit: Get in! Di4000-N says hello!

I've got to admit I have absolutely no idea what you're talking about at all but if it helps archive more of our history that I'm all for it.

Haha, well, all the technical bits aside, essentially these cable boxes (generally, the Pace DiTV1000 I have notwithstanding) won't turn on at all, they'll just stay black when you turn them on, or they'll just endlessly show an NTL or Virgin or whatever logo, if they're not plugged into a cable socket (and more specifically a cable socket for the correct service in the correct region).

So the plan is to feed them signals that mimic the ones that came down the cable so that they work again, both for the fun of being able to watch your own TV channels on them (transmitted from a PC) and for being able to record how they looked and worked for historical preservation.

I realise there's a lot of technical stuff in this thread, so I'm trying to keep it a bit lively with screenshots so it's a bit more visually obvious what's going on between all the talk of NITs and EITs and PIDs and whatnot

I know a little bit about how the cable networks work. Probably not enough to help you get the boxes working, but there may be a few interesting bits I can still remember.

There were (and still are) differences between the way that the three cable networks actually worked. Cable and Wireless and Telewest were similar, but the ntl network had some differences in the way the data in the DVB-C transport streams was structured. These differences are still in place today with Virgin Media sending slightly different signals to regions that were originally ntl areas. If you have boxes from different regions then you may find that a signal that works with one may not work with another.

You mentioned that one of the boxes was running CR1, this was an early version of the software used by ntl. It was quite basic and lacked interactive functionality (that came in CR2). If you've been able to get this box to boot it's probably because it's not got any of the more advanced features that came in later versions of the software.

The software that ran on these boxes in later years was based on the Liberate middleware platform. I believe that large parts of the UI were actually web based, running in the Liberate browser. Whilst some parts of the EPG application would have been in the software running on the box, some parts of the UI may have been loaded from servers on the network. I know that some data relating to the Liberate platform is broadcast via the DVC-C transport streams. I'm not sure what this data was used for (it may have been something like the configuration data used to build the home menu), but you may find that some of the boxes either wont boot or wont work correctly without this data.

Virgin Media have been removing the older boxes from their network for a number of years and the last two models of box running Liberate based software were discontinued last month, so it wouldn't surprise me if the infrastructure this TV platform needed was currently in the process of being ripped out of all of the head ends.

The boxes got their EPG data from the DVB transport stream, but the amount of data would vary depending on the model of the box and version of software. In the earlier years all of the boxes had a seven day EPG, so a full seven days worth of data was broadcast over the network on all transport streams. As the number of channels increased this was reduced to three days and then to just one day as the older boxes didn't have enough memory to store all the EPG data for all of the channels. The V+ box did support a full 7 day EPG and was the only type of box that used the full EPG data which was only broadcast on one transport stream.