Teletex » History » Version 3
laforge, 01/15/2023 05:38 PM
| 1 | 1 | laforge | h1. Teletex |
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| 2 | 2 | laforge | |
| 3 | 3 | laforge | Teletex is a mostly-forgotten technology somewhere between [[Telex]] and [[Telefax]]: |
| 4 | * like Telex, it transmitted data as characters |
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| 5 | ** however, Teletex supports a more complete alphabet with lowercase characters and special characters (Telex: Only 5-bit uppercase) |
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| 6 | * like Telefax, it transmitted formatted entire pages/documents |
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| 7 | ** however, Teletex transmits the text characters and their formatting (Telefax: A raster-pixel-image). |
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| 9 | Teletex was invented aroud 1981. German operation was from 1981 through 1993. |
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| 11 | h2. Terminal Devices |
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| 13 | Early/Simple Teletex devices are typically built from pre-existing daisy-wheel typewriters with single-line memory/editing/display capability. Those typewriters were extended with additional communications hardware and software in order to receive and/or transmit in Teletex format. |
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| 15 | Later, more complex Teletex devices were text/word processing systems, either dedicated or in the form of personal computers. Those were then likewise extended with a Teletex communications hardware + software. |
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| 17 | 2 | laforge | {{child_pages()}} |
| 18 | 3 | laforge | |
| 19 | h2. Network |
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| 21 | Teletex is designed to use a [[CSPDN__Datex-L|CSPDN]] (circuit-switched public data network). The Teletex user equipment interfaces to the network via a 2400 bps synchronous [[X21|X.21]] interface. |
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| 23 | h2. Relevant Specifications |
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| 24 | |||
| 25 | * ITU-T F.200 (Teletex service) |
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| 26 | * ITU-T T.61 (Teletex character set) |
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| 27 | * ITU-T X.21 (interface) |
