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Old 6th Mar 2018, 11:32 pm   #1
cmjones01
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Default Prestel and Micronet 800 dialup - how did it work?

A conversation elsewhere reminded me of this, and I know there are some telecommunications experts on here.

Back in the mid-to-late 1980s, I used to use a BBC Micro and V23 modem to access Prestel and Micronet 800. I can still remember the phone number: 01223 4411. The of thing is that I was calling from the 01223 area code, but still had to dial the full number. Just dialling 4411 wasn't enough. Phone numbers in the 01223 code normally had 5 (6xxxx) or 6 (2xxxxx, 3xxxxx or 8xxxxx) digits anyway.

What was going on here? At the time it seemed very strange, compared with the familiar patterns of normal phone numbers. Any technical insight would be much appreciated.

Chris
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Old 7th Mar 2018, 12:18 am   #2
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Default Re: Prestel and Micronet 800 dialup - how did it work?

In most "director" areas the access number was on short codes 618 and 918. The full number was (std) 618 1111 and (std) 918 1111 The Prestel computers seemed to operate in isolation from each other and had poets names, I think the primary Manchester one was Wordsworth.

I think Micronet 800 was just a magazine of pages on Prestel (I could be wrong) but there were several private Viewdata systems using the same technology.
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Old 7th Mar 2018, 1:01 am   #3
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Default Re: Prestel and Micronet 800 dialup - how did it work?

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In most "director" areas the access number was on short codes 618 and 918. The full number was (std) 618 1111 and (std) 918 1111 The Prestel computers seemed to operate in isolation from each other and had poets names, I think the primary Manchester one was Wordsworth.

I think Micronet 800 was just a magazine of pages on Prestel (I could be wrong) but there were several private Viewdata systems using the same technology.
Yes, Micronet800 was a Closed User Group (CUG) in Prestel-speak.

Way ahead of its time with email, online banking, software downloads, social media (user-editable 'Galleries') and even a real time (ish) chat room. Your email address ('mailbox number') was your telephone number without the leading 0 unless you requested a special private one.
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Old 7th Mar 2018, 12:12 pm   #4
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Default Re: Prestel and Micronet 800 dialup - how did it work?

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Originally Posted by cmjones01 View Post
I was calling from the 01223 area code, but still had to dial the full number. Just dialling 4411 wasn't enough.
If you were calling that number in the early 1980s, you were calling a London (01) number - 223 4411. You would have been in London and could have called just the last seven digits?
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Old 7th Mar 2018, 12:33 pm   #5
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Default Re: Prestel and Micronet 800 dialup - how did it work?

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Way ahead of its time with email, online banking, software downloads, social media (user-editable 'Galleries') and even a real time (ish) chat room. Your email address ('mailbox number') was your telephone number without the leading 0 unless you requested a special private one.

You could send a Telex message for 50p.

Meaningful security was non existent (remember how members of the Royal Family were hacked)

The Post Office initially wanted the terminal's account number to be permanently associated with a given terminal, and the customer was given no clue as to how it could be changed.
The NV RAM into which the ID and phone numbers was stored on some terminals were far from NV, and would corrupt the numbers spontaneously, so it was essential I kept a record of the ones I looked after.
Looking at my Letts diary for 1986 I have a couple listed for Granada TV, 10 digit user ID and a 4 digit PIN that was normally keyed interactively by the user, but I found it could all be lumped as a 14 digit string.
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Old 7th Mar 2018, 2:17 pm   #6
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Default Re: Prestel and Micronet 800 dialup - how did it work?

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Quote:
Originally Posted by cmjones01 View Post
I was calling from the 01223 area code, but still had to dial the full number. Just dialling 4411 wasn't enough.
If you were calling that number in the early 1980s, you were calling a London (01) number - 223 4411. You would have been in London and could have called just the last seven digits?

As Chris still (in part) has Cambridge listed in his profile I assumed he had forgotten just when PhONEday was, and when 0223 became 01223
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Old 7th Mar 2018, 3:25 pm   #7
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Default Re: Prestel and Micronet 800 dialup - how did it work?

I seem to recall (sorry!) that I dialled 9 292111 from the Flax Bourton exchange outside Bristol. I've no idea whether that helps answer the original question though.
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Old 7th Mar 2018, 11:02 pm   #8
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Default Re: Prestel and Micronet 800 dialup - how did it work?

Ah yes, I'd forgotten about PhONEday. This was definitely before that. It was certainly a Cambridge number, so it must have been 0223 4411 (or was it 0223 1111? I've probably got it on a BBC floppy image somewhere...). The point was to get access to Prestel at local call rate, so it wouldn't have been a London number.

Thanks for all the Prestel memories! It seems like there were quite a lot of different dialup numbers used for it in different areas, despite the nominal short code for access.

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Old 7th Mar 2018, 11:55 pm   #9
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Default Re: Prestel and Micronet 800 dialup - how did it work?

These stories of Prestel and its phone numbers have brought back some memories for me.

Back in 1989 I got hold of a secondhand Prestel terminal with colour monitor based on the Philips KT3 TV chassis. I lived in the Whitchurch area of Bristol at the time. The Prestel terminal was pre-programmed to dial a 6-digit Bristol number; it also had the user ID and password stored inside and automatically entered them when it connected. This was all very well, but customers in Whitchurch were required to dial 9 to reach Bristol phone numbers, just like Dai Corner said in an earlier post about Flax Bourton near Bristol, thus the automatic connection always failed from Whitchurch. I couldn't work out how to change the stored phone number - maybe it needed the password which I wasn't supplied with.

Eventually I did get it to connect, using an extension phone, but it wasn't easy. I seem to recall picking up the extension phone, dialling 9 for Bristol, then starting the Prestel terminal and hanging up the extension phone as soon as the terminal had started to go online, but before it had started dialling. I can't remember the exact procedure now, suffice to say I did get online after some effort, but quickly lost interest and got rid of the terminal very soon after.

I vaguely recall that the Prestel phone number from High Wycombe was a 4-digit Luton number, something like 0582-8181 where 0582 was the old STD code for Luton - it's now 01582 since "Phoneday". (Calls from High Wycombe to Luton were charged at local rate, yet bizarrely calls to places like Reading and St. Albans were non-local, even though they were closer.) There were still the odd 4-digit numbers in use at the time, for example the speaking clock was 8081 until the early 1990s when it was changed to 123. Again, until the early '90s, some of the villages in the High Wycombe area still had 4-digit phone numbers, like Great Missenden and Penn. These became 6-digit numbers by adding the prefix 86 to Great Missenden numbers and 81 to Penn numbers. I'm not sure what happened to the Prestel phone number. Prestel seemed to have disappeared by the mid 1990s. Last time I saw it was in a travel agent's shop. Instead of a dedicated Prestel terminal, they were using a PC with terminal emulator software.
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Old 8th Mar 2018, 12:59 am   #10
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Default Re: Prestel and Micronet 800 dialup - how did it work?

It's surprising how challenging even a 1200/75 baud connection was at this time.

Granada TV trialled what was probably the first example of electronic audience participation.
The programme eventually became " The Granada 100" and there were (notionally) 100 audience members with terminals set up so they could vote on the big story of the day.

My involvement was supplying the equipment, two Labgear Viewdata terminals. They needed to communicate directly with the audience research people AGB/BARB at their
Hanger Lane, London headquarters. The programme went out at about 6pm and the idea was at the end the viewdata box would show the voting result graphic.

The first few programmes did not go too well with lot's of random gibberish on both the primary and backup terminal.

Someone had the idea to dial the boxes in at lunchtime, and provided the connection was clean, just keep them on-line until showtime.
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Old 8th Mar 2018, 12:20 pm   #11
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Default Re: Prestel and Micronet 800 dialup - how did it work?

Id forgotten that the V.23 protocol had no error correction, hence the problems Graham recounts. Telephone lines were often noisier in those days too.

Actually, the 75bps back channel was designed to be used for this purpose but was repurposed for the keyboard input according to
https://en.m.wikipedia.org/wiki/ITU_V.23
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Old 8th Mar 2018, 4:53 pm   #12
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Default Re: Prestel and Micronet 800 dialup - how did it work?

7 bit + 1 (even) parity in both directions is all you got (IIRC)
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Old 8th Mar 2018, 6:55 pm   #13
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Default Re: Prestel and Micronet 800 dialup - how did it work?

I remember using Prestel using a very rare, Wren computer. Monochrome CRT, and twin 5.25 floppies. At that time weekends were free, but weekday usage was charged to the account holder. I once used it on a bank holiday, and my dad got a bill as it was classed as a weekday!
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Old 8th Mar 2018, 7:08 pm   #14
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Default Re: Prestel and Micronet 800 dialup - how did it work?

IIRC Bookmakers used to use Prestel to share the latest odds, betting pattens etc, until quite late in the day.
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Old 8th Mar 2018, 9:46 pm   #15
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Default Re: Prestel and Micronet 800 dialup - how did it work?

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IIRC Bookmakers used to use Prestel to share the latest odds, betting pattens etc, until quite late in the day.
I haven't any recollection of that, perhaps some of the independents did.
I was involved with stripping out the old Extel system (remember the "blower") and the maintenance of the SIS system that replaced it. All the SIS graphics was SAA5050 teletext/viewdata style, so it certainly looked like Prestel.

One site I went to was different, they couldn't get planning permission for a satellite dish so I had to install a special tuner in the SIS computer which extracted some closed-user pages from Teletext (ITV I think)
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