Teletext to Viewdata server

[John_Newcombe]

Of course you can use the picture! I've also got pictures of Telstar on the Italian MSX terminal and the Telcom Ace if you'd like?

Thanks and yes to any others you may have.

I keep meaning to write up how I'm using these terminals, but we could all die of old age waiting for that to happen.

As I am quite old now maybe I could get the details from you I have a Grandstream HT502 ATA connected to a SIP already, at the moment this is connected to a real modem with a small Python server routing it through to Telstar. It's not that reliable at the moment but just needs a few hours work. I have never had any success in getting Asterisk running properly so have given up on a couple of occasions. Maybe with you help I could try again.

[tjewell]

Would that cause more problems than it solved?

I'm not sure that there is actually a 'problem' that needs solving. Since the 920-character limit was specific to Prestel, and not a guarantee made by the Viewdata specification, no terminal (whether ancient or modern) should be relying on it. Even with the limit I can't see that it necessarily prevents the TD1616 from scrolling, since only a few control characters are needed to move into the bottom row.

I agree. I wrote a little 920 character proxy, just to see what would happen, and it's easy to trip up. As you say, it's easy to use control characters to get to the foot of the page, without hitting the 920 limit. It's also tripped up when you write double height characters onto line 23 too (I think, certainly looks like it on pages 100 and 900). I'm sure I could build a little proxy server that catches all this and makes the Td1616 behave - but given I am probably the entire active Td1616 user community at the moment, I'm not putting it as a high priority job!

Thanks for your help everyone.

[Soruk]

I've made a small change to the page numbering - new connections get page 9FF by default (instead of 900), it has the same content as 900 used to have. As such, 900 is now the home screen for the local Matrix Teletext service, and I've removed the Teefax branding from the 9xx pages except 9FF.

Additionally, when the server detects a connection from TELSTAR's gateway service (it uses the source IP) clock updates are disabled and the minimum page update interval is 20 seconds. Otherwise, there are just too many screen updates for a 1200bps connection to handle!

[Deleted User 9295]

I've made a small change to the page numbering - new connections get page 9FF by default (instead of 900)

Just to add that my telstar.bbc client, when running on a device without a keyboard (e.g. Android or iOS), provides no means of entering 'hexadecimal' page numbers. Wikipedia confirms that "the Prestel system was originally designed to be operated solely by means of a simple numeric keypad" (0-9 , * and #).

[Soruk]

I've made a small change to the page numbering - new connections get page 9FF by default (instead of 900)

Just to add that my telstar.bbc client, when running on a device without a keyboard (e.g. Android or iOS), provides no means of entering 'hexadecimal' page numbers. Wikipedia confirms that "the Prestel system was originally designed to be operated solely by means of a simple numeric keypad" (0-9 , * and #).

Press *, this switches on the cursor until the next screen refresh, and makes use of thing you added for TELSTAR to enable the keyboard. Also, # advances to the next available page, taking into account hexadecimal. I'm not going to worry about the numeric keyboard limitation as that would make the weather page on Telstar unusable, and CCL4 impossible as you can't log in.

[Deleted User 9295]

Press *, this switches on the cursor until the next screen refresh

Thanks, that's a useful tip although of course it's specific to your service. I've always assumed that hexadecimal page numbers are not intended for direct navigation, other than for 'engineering' purposes. The keypads I remember were 12 keys in the 'telephone' pattern:

Code: Select all

1 2 3
4 5 6
7 8 9
* 0 #

rather than the 'calculator' pattern with the first and third rows swapped. I assume this was a hangover from pulse-dialling telephones when 0 was adjacent to 9 (and sent 10 pulses). Occasionally there might have been a fourth column but still no way of entering E or F:

[Soruk]

Press *, this switches on the cursor until the next screen refresh

Thanks, that's a useful tip although of course it's specific to your service.

True - but my service is (as far as I know) the only Teletext to Viewdata service. Sending * just turns the cursor on, similarly to the login screen on CCl4 and the weather page on Telstar both turn the cursor on for the input fields, and your client triggers on the cursor-on code to bring up the keyboard on Android (and iOS?). This is documented on P901 (About this server) on page 2/2.

I've always assumed that hexadecimal page numbers are not intended for direct navigation, other than for 'engineering' purposes. The keypads I remember were 12 keys in the 'telephone' pattern:

That is true - but as the 9xx series are themselves out of range for a "normal" Teletext service (11 bits - 000-7FF or 100-8FF), and only available via my server on a Viewdata client, I've chosen not to follow the rules too closely, as most clients these days (certainly all software ones) have the capability to send pretty much any character. On a real TV, dialling P900 would bring up P100. Well, it certainly used to when I messed around with dialling random numbers on the keypad when I was a kid

[Deleted User 9295]

That is true - but as the 9xx series are themselves out of range for a "normal" Teletext service (11 bits - 000-7FF or 100-8FF)

Indeed, but I assume 900-999 are legitimate page numbers for Viewdata in which case I would argue they're not out of range for a 'Teletext to Viewdata gateway'.

most clients these days (certainly all software ones) have the capability to send pretty much any character.

My telstar.bbc client, when running on a mobile platform or smart TV, wasn't intended to be able to send anything other than 0-9 * and # (except when the on-screen keyboard is enabled on a Prestel response frame). Making it do so involves a 'cheat'.

[Soruk]

That is true - but as the 9xx series are themselves out of range for a "normal" Teletext service (11 bits - 000-7FF or 100-8FF)

Indeed, but I assume 900-999 are legitimate page numbers for Viewdata in which case I would argue they're not out of range for a 'Teletext to Viewdata gateway'.

most clients these days (certainly all software ones) have the capability to send pretty much any character.

My telstar.bbc client, when running on a mobile platform or smart TV, wasn't intended to be able to send anything other than 0-9 * and # (except when the on-screen keyboard is enabled on a Prestel response frame). Making it do so involves a 'cheat'.

Maybe it is a cheat. Also, my server is so far removed from a Prestel-style Viewdata server with its *PAGE# routing codes - it's basically doing its own thing to mimic a TV's Teletext interface (minus fastext, as row 25 isn't available) over IP, sending the content in a way a Viewdata client can show it as it's intended to be shown. Really, the entire server is a cheat, as Teletext was never intended to be IP-streamable, whereas Viewdata over IP is hardly a stretch beyond using dial-up as a bearer.

[Soruk]

Adding to the list of cheats, FASTEXT support is enabled. Details are on P904, but the cheat is the Fastext labels line can replace the clock line. (If no Fastext line on the page, the clock is displayed as usual)

No specific client support is required - though the "cheat" above to get the keyboard displayed will be needed for RIchard's client on mobile platforms.

[Deleted User 9295]

Adding to the list of cheats, FASTEXT support is enabled..

You'll call me pedantic, but arguably the most important aspect of Fastext was the cacheing of the linked pages in the receiver, so that they could be loaded 'instantly' (whether accessed via the coloured buttons or directly by entering the page number), hence "fast". Given that your 'Teletext via Viewdata' server supports random-access to pages anyway, albeit rather more slowly than loading them from local memory, that aspect of Fastext has always been supported.

Presumably what you're talking about are the coloured labels, which is but one small aspect of Fastext, albeit the one which is most instantly recognisable.

[Soruk]

Adding to the list of cheats, FASTEXT support is enabled..

You'll call me pedantic, but arguably the most important aspect of Fastext was the cacheing of the linked pages in the receiver, so that they could be loaded 'instantly' (whether accessed via the coloured buttons or directly by entering the page number), hence "fast". Given that your 'Teletext via Viewdata' server supports random-access to pages anyway, albeit rather more slowly than loading them from local memory, that aspect of Fastext has always been supported.

Presumably what you're talking about are the coloured labels, which is but one small aspect of Fastext, albeit the one which is most instantly recognisable.

You are absolutely right. And yes, it's the coloured labels feature that is now supported. So, finally, Bamboozle is now playable!

[tjewell]

Oh and on the subject of keyboards vs number pads, that sometimes trips me up with this machine!

[Soruk]

Oh and on the subject of keyboards vs number pads, that sometimes trips me up with this machine!IMG_20200222_155918.jpg

I can see that limitation. It is possible to get to the hex pages via the # key, for example you can dial 919 then press # to get to page 91A, and again to get to 91B. But without a proper keyboard you won't be able to use Hold, or the new Fastext support.

[tjewell]

But without a proper keyboard you won't be able to use Hold, or the new Fastext support.

Apparently - according to the manual - there is an additional plug-in keyboard for this machine. I have never seen one. Again, I suspect the user base of people still playing with this machine might be hovering around one, so it's not worth making any exceptions for it. Although it's not the only keypad-only machine. The first Tandata only had a keypad too, and perhaps there are others. Again, not sure what the 'standard' had to say about this.

[guesser]

You are absolutely right. And yes, it's the coloured labels feature that is now supported. So, finally, Bamboozle is now playable!

Navigation via Full Level One Facilities

[marrold]

Hi all, sorry to bump an old thread.

Soruk - I understand you run the Telstar / Teefax gateway? I was wondering if its open source and available online somewhere?

I'm planning on providing dial up access to John's Telstar service at https://www.emfcamp.org/ in a couple of weeks and someones just announced they're making a Teletext service (EMFFAX) so it would be could if we could gateway from Telstar into EMFFAX.

AFAIK they're feeding TTI files into vbit2 on their side.

Thanks

[Soruk]

If they're making the TTI files available via version control then I could create a server for this.

[marrold]

That would be great, thank you. Does Git work for you?

Is there a way to contact you directly? I can't PM you because I'm new to the forum - perhaps if PM me first I can reply.

Thanks again

[Soruk]

Git is fine - and I would only need read access.

[marrold]

Thanks, I will speak with them and see if they can push them to git, then I'll get in touch.

I couldn't reply to your PM - I've reached out to the mods

Thanks again

[Soruk]

Thanks, I will speak with them and see if they can push them to git, then I'll get in touch.

I couldn't reply to your PM - I've reached out to the mods

Thanks again

You can email me at my username at domain eridani.co.uk

(Sorry for the awkward description, don't want it scraped by a spam bot.)

[Soruk]

To all users of my server:

The server has moved to teletext.matrixnetwork.co.uk:6502

I am running a forwarder on the old server for now, but please update your links.

Update: The old server is now gone. Pegasus no longer resolves in the DNS.