Re: controll sequences

From: Philippe VERDY (
Date: Wed Jun 08 2005 - 16:39:10 CDT

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    > De : "Andrew West" <>
    > On 07/06/05, Matthias-Christian Ott <> wrote:
    > >
    > > For what are the controll sequences in ascii (except \n & \t) useful?
    > >
    > The facetious answer is that they are useful if you use them. Although
    > most of the control characters are no longer widely used in text other
    > than 0x09 (Tab), 0x0A (LF) and 0x0D (CR), as well as 0x00 internally
    > as a null terminator for strings, many of the ASCII control characters
    > are still widely used in communications protocols. I myself recently
    > used a simple serial protocol that delimited text with 0x02 (Start of
    > Text) and 0x03 (End of Text).

    I admit that I worked on such protocol between 1983 and 1988, when the Internet was nearly inexistant. It was used to communicate with X25 adapters (at that time, in France we had the old and slow "Minitel" terminal, but this was still a revolution because it created the online market activities). The Minitel is still not dead in France, but it is no longer distributed as a terminal but as a software. There are no more investments about it, and it mostly remains some public utilities, or it is maintained for those that don't have or want a computer, simply because it was really simple to use (but expensive...).

    From this time, it remains the old Teletext encoding standard (which unlike Unicode, encoded diacritics BEFORE the base letters, and encoded also rich-text enhancement, and dynamic cursor management in a way similar to VT and ANSI terminal protocols) using the general ISO 2022 extension mechanisms. The Teletext is still used for TV guides on broadcasted analogic channels (whose death is now programmed, since numeric TV broadcast is now open...), where it has kept the poor display resolution, very limited number of colors, the fixed width bitmap fonts, and small amounts of text or graphic information per page.

    But when later the SMS system was created for mobile phones, it was perceived as being even poorer. Despite this, the system was simple enough to get much success and to recreate a large market for simple services.

    Conclusions about this: things don't need to be complicate or very advanced to be successful and widely accepted by the public. In fact, users DO want things simple to use.

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