Introduction to the TELSTAR Viewdata system

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The TELSTAR Viewdata System is a modern application that provides a simple viewdata/videotext platform in the style of Prestel (https://en.wikipedia.org/wiki/Prestel).

The aim of the software is to provide a Viewdata experience for anyone who is interested in how thinng 'used to be'. The modern service uses an internet connection rather than over the public switched telephone network (PSTN). The service currently runs out of Digital Ocean's data centre in London and can be accessed using a Telnet modem (see below).

Connecting and Using the Service

The service can be accessed using a Telnet modem, such as the modem described by Daniel Jameson (http://www.amibay.com/showthread.php?99878-WiFi-retro-Modem-for-under-a-tenner) or a WiModem232 (https://www.cbmstuff.com/proddetail.php?prod=WiModem232OLED).

Terminal software needs to be able to handle the Viewdata/Prestel format, packages are available for the BBC Micro such as Commstar. Set the speed to 2400baud (both directions) and set the parity to None with 8 data bits and one stop bit.

There are three instances of the TELSTAR service, these are named 'CURRER', ELLIS' and 'ACTON' respectively. The first two are identical and are available at the following addresses.

   Url:  glasstty.com
   Port: 6502
   Url:  glasstty.com
   Port: 6503

The third service is used to test new features and may be subject to short periods of interruption.

   Url:  glasstty.com
   Port: 6504

Content

Currently the system takes several news feeds from the BBC and Reuters and others, and financial information from Google sheets. In addition a small computing section has been included which includes a Telesoftware service (see below) as well as a single feed from the stardot.org.uk forums.

For a full list of the content available please see the TELSTAR Directory. The content is a little weak at the moment, especially on the intermediate pages, however, with the development of the Teletext convertor complete, It will be possible to edit pages using a Teletext editor such as the one at https://edid.tf, and import all or part of a page into TELSTAR, converting to Viewdata format in the process. Therefore, as the system expands, it is hoped that the content will become more refined.

Routing

Routing is loosly based on the Prestel system, where navigation can take place by following the menu system, additionally, direct access to a page can be gained by using the special combination shown below.

   *<page number>#
       
       e.g. *890#
       

'Routing Map' support has been added which means that when following the menu selections pages, data from different IPs can be displayed. This mimics the original Prestel Cross Referencing service and allows full interlinking of content.

There are a few differences between Prestel and Telstar. Under Prestel, page rendering could be interrupted with a keypress. This was very useful in navigating deep hierarchical trees. This does not work with Telstar at the moment due to some nuances with streaming data to a TCP socket whilst listening at the same time. This is less of an issue with Telstar than it would have been with Prestel, as the Prestel database was far larger and the system was therefore far more hierarchal than Telstar. It also helps if Telstar is accessed at the recommended baud rate of 2400 baud rather than 1200 baud that Prestel used.

Prestel used to have a history of three pages allowing the special sequence *# to move back one step. Telstar has an unlimited history. All other special sequences used by Prestel are supported.

Telesoftware

The protocol used for Telesoftware is described in the document File:Prestel Telesoft Protocol Low Res.pdf.

The provided TEST program is a tokenised BBC BASIC program aimed at providing a simple mechanism for users to test their respective client systems.

More software will be published as it becomes available.

Copyrights and Trade Marks

It is the aim of TELSTAR to respect all copyrights and trade maeks. Please let me know if you are affected by any software and content that is published on the system.

Gateway Facilities

TELSTAR now features Gateway access to other viewdata systems. At the time of writing it is possible to 'gateway' to CCL4, over at fish.ccl4.org, and to the test version of TELSTAR for a sneak preview of any new features.

In addition, it is also possible to access some none viewdata systems, see #Colossal Cave Adventure below.

Gateways.png

Colossal Cave Adventure

TELSTAR, via its #Gateway Facilities can now access the famous 360 point version of Colossal Cave Adventure.

Colossal Cave Adventure (also known as ADVENT, Colossal Cave, or Adventure) is a text adventure game, developed originally in 1976, by Will Crowther for the PDP-10 mainframe. The game was expanded upon in 1977, with help from Don Woods.

Gateway Adventure.png

Development Aims

The system has seen incremental improvements over the last few weeks and is now a reasonably stable viewdata platform. Content is generated automatically with data being updated every 10 minutes. Whilst this is ideal from a content management perspective, it requires that graphical content is created automatically also. This has shown itself to be quite challenging. It is an aim, especially as content grows, to develop this aspect further.

The addition of themes for the generic page elements e.g. navigation and system messages etc. is the next planned development activity. The aim is that these elements adapt to the page style of the automatically created content to create a more coherent use of colours etc.

Technical Details

The TELSTAR system runs on a Digital Ocean cloud based server hosted at glasstty.org, port 6502. The software is written in Python 2.7 and runs on Debian Linux (Jessie) and is managed by systemd.

Currently only a single service is running, referred to as Monty, however, the service can accept many concurrent connections. The service also includes a Telnet negotiation process that sets compliant Telnet clients to character mode as apposed to line mode. This is included to better support Telnet modems and to allow simple connectivity tests to be made using a standard telnet client.

Acknoledgements

Artwork

Technical Help

References

  • [1] Fedida, S. & Malik, R. (1979) The Viewdata Revolution Associated Business Press
  • [2] Martin, J. (1982) Viewdata and the Information Society Prentice Hall
  • [3] Money, S.A. (1979) Teletext and Viewdata Newnes
  • [4] Stokes, A. (1980) Viewdata: a public information utility (2nd Ed.)