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Geek Culture / Anyone know about teletypesetting (TTS)?

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Jeku
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21
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Joined: 4th Jul 2003
Location: Vancouver, British Columbia, Canada
Posted: 30th Jan 2005 06:51 Edited at: 30th Jan 2005 07:03
There's a question on my assignment that talks about how, in the 1970s, many newspapers used a 6-bit code called TTS to send and receive news stories. The character set allowed over 100 characters including uppercase, lowercase, and special formatting. It asked how this could be accomplished.

Since 2^6 is just 64, does anyone know how this was done? I tried Google and just can't seem to find the info. One of my ideas was that they would send 2 data blocks per character to handle lower and uppercase, but then wouldn't that just be 12-bit?

Argh.

EDIT:

This is my answer--- I'll just leave it unless someone knows the "official" answer:

Quote: "The only way that I can imagine being able to fit over 100 characters in a 6-bit code would be to reserve special codes for SHIFT, UNSHIFT, and other formatters. If the data were to have a capital letter, it would send a SHIFT code, then the letter, then an UNSHIFT code, then the reset of the sentence, and lastly the period. Certain punctuation could be sent as an uppercase to a number, i.e. SHIFT then 2 could be a period or a comma."



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IanM
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Joined: 11th Sep 2002
Location: In my moon base
Posted: 31st Jan 2005 21:47
You have it right - http://homepages.cwi.nl/~dik/english/codes/6tape.html#start

Control codes are marked on the grids in red. The ones you should look at are:

- FS (Figure shift), LS (Letter shift)
These shift the grid used to the left (FS) or the right (LR).

- UR (Upper rail), LR (Lower rail)
These shift the grids up (UR) or down (LR).

The TTS lower rail is identical on both British and American layouts, but they had their own versions of the upper rail

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