[Stooky Bill]

We should remember local teletext services were still originated at the individual local ITV premises post 1992, only the national teletext service changed.

That is true, but before 1993 the local teletext was all from Oracle, albeit I think with the actual content provided by the ITV companies.

After 1993 the ITV companies got responsibility for subtitling and the 600 magazine (the 'Ancillary Teletext Service) which could only be TV related content. That was originated at the ITV company. Channel 4 had the same but the 400 magazine, and Channel 5 with 500

Meanwhile Teletext Ltd also provided local content but it all came from them and their providers. They were more local than ITV, as their service originated at the transmitter sites and they could potentially broadcast 25 different teletext services on both ITV and Channel 4.

[Bluecortina]

That is true, but before 1993 the local teletext was all from Oracle, albeit I think with the actual content provided by the ITV companies.

After 1993 the ITV companies got responsibility for subtitling and the 600 magazine (the 'Ancillary Teletext Service) which could only be TV related content. That was originated at the ITV company. Channel 4 had the same but the 400 magazine, and Channel 5 with 500

Meanwhile Teletext Ltd also provided local content but it all came from them and their providers. They were more local than ITV, as their service originated at the transmitter sites and they could potentially broadcast 25 different teletext services on both ITV and Channel 4.

Pre 1993 the national teletext service was (finally) originated at ITN and this included the local teletext services for LWT (and I presume Thames). It was one of the reasons ITN was permanently fed to Thames and LWT. This ITN teletext feed was bridged across to all the Thames/LWT's main outgoing circuits which then of course fed all the other ITV companies who inserted their own local content over the London regional content.

Post 1993 London's regional teletext service was inserted at TLS. But there was no actual derivation of content there, this was provided by a third party who modemed it across as required. I think you posted a link earlier to a chap who used to work on this service and has much more detail. We didn't really need to touch it, it was all Softel kit and I do not recall it ever going wrong. I think they may be an IBA engineering information booklet on the origin of teletext distribution arrangements which started at South Bank and Thames but was eventually amalgamated at ITN.

Edited to add. Have a look here if you are interested in the history and development: Number 20 is the pertinent booklet.

u.pcloud.link 

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[Technologist]

The government wanted to auction off the teletext spectrum to private companies within sectors such as banking. …..

Here at page 4 is the BBCs take on the broadcasting bill …and David Mellor!!
www.bbceng.info 
But as it’s “spare” data capacity continued being under pressure for some years
Hence the BBC Ceefax engines outputting on 13 1/2 line pairs
but the emission was on 12 line pairs including the commercial datacast
Hence having less than 1% redundant packets ….
BBC inserted Ceefax at regional centres and used clever MRG data bridges that they specified .

The use of broadcast services for commercial data was rather limited …..
betting, duff credit cards, LSE , all had time sensitive data to lots of outlets .
BMW used car update less so but it was more economic to mail out CD weekly and just use the broadcast for updates …
The BBC used data broadcasting for Presfax and Telfax (see p7) and for a short time talkback to news obs .

[Stooky Bill]

Post 1993 London's regional teletext service was inserted at TLS. But there was no actual derivation of content there, this was provided by a third party who modemed it across as required.

Yes that was the 'Ancillary Teletext Service' on P600-699 as I say it was only allowed to have programme related content so not to compete with Teletext Ltd.

London's didn't start till late on, possibly September 1993, it changed between LWT, Carlton and GMTV. As I mentioned, Westcountry's was up and running a lot earlier, there's was done in house I think. Most regions including London was done by Intelfax, a stones throw away from TLS in Lower Marsh


The London news, travel, adverts etc were Teletext Ltds thing, they came from Fulham and I settled at Crystal Palace

[WillPS]

How did the GMTV ancillary service work then, since their route to transmission was via each region (unlike TVam)? In Central land I seem to remember page 600 (and the header legend on the ancillary range) would change to GMTV Text between 0600 and 0925, but all the other pages of Centext would still be there.

Was this just something each region handled on GMTV's behalf?

[Steve in Pudsey]

I remember early on GMTV replaced the regional 600 magazine during their hours but later the regional YTV magazine went out 24/7 with GMTV content on pages 640-649 at all times.

[Stooky Bill]

How did the GMTV ancillary service work then, since their route to transmission was via each region (unlike TVam)? In Central land I seem to remember page 600 (and the header legend on the ancillary range) would change to GMTV Text between 0600 and 0925, but all the other pages of Centext would still be there.

Was this just something each region handled on GMTV's behalf?

My understanding is that at the regional centres their presentation area was switched out of line during GMTV and the signal path went through their news gallery.

If so my guess would be that the teletext for each company was added before that switch and GMTVs passed through the gallery. Therefore the teletext service broadcast just followed which was on air.

The main Teletext Ltd service didn't care which company was on air as it was added right at the last point of the TX chain

[WillPS]

My understanding is that at the regional centres their presentation area was switched out of line during GMTV and the signal path went through their news gallery.

If so my guess would be that the teletext for each company was added before that switch and GMTVs passed through the gallery. Therefore the teletext service broadcast just followed which was on air.

The main Teletext Ltd service didn't care which company was on air as it was added right at the last point of the TX chain

That'd make sense if the regional ancillary service disappeared during GMTV's hours, but they didn't (at least not in Central nor in Yorkshire by the sounds of things).

I suspect that either the whole thing was added locally when the news was, and each region did something to switch between presenting as their own service or GMTV Text + redressing page 600. Unless it would have been possible for GMTV to emit a single page ancillary service on Page 600 and for the region to add the rest of the range?

[Stooky Bill]

That'd make sense if the regional ancillary service disappeared during GMTV's hours, but they didn't (at least not in Central nor in Yorkshire by the sounds of things).

I suspect that either the whole thing was added locally when the news was, and each region did something to switch between presenting as their own service or GMTV Text + redressing page 600. Unless it would have been possible for GMTV to emit a single page ancillary service on Page 600 and for the region to add the rest of the range?

It could be that the service changed in each region at 6am, after all GMTVs and almost all the regions (I think Westcountry was the exception) were done by Intelfax.

It sounds like it changed - the early days it was a seperate service for GMTV and later on it was mixed? The mixed version with GMTV and the regional pages would have been just Intelfax creating each regional version with GMTV pages that were the same on each

A quick look at The Teletext Archive and yes there were some GMTV pages were on p640 in Central in the evenings but of course it's difficult to see what actually went out between 6 and 9:25 unless there's a capture from that time slot. I imagine even if the pages were the same the header will have changed

www.teletextarchive.com 

Details - Teletext Archive
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[WillPS]

Ah, a totally separate concern adding the ancillary service would make sense - I hadn't thought of that.

It'd be interesting to know how Westcountry handled it in that case. I can't see any recoveries from GMTV hours on that site.