Teletex » History » Revision 3
Revision 2 (laforge, 09/28/2022 05:17 PM) → Revision 3/9 (laforge, 01/15/2023 05:38 PM)
h1. Teletex Teletex is a mostly-forgotten technology somewhere between [[Telex]] and [[Telefax]]: * like Telex, it transmitted data as characters ** however, Teletex supports a more complete alphabet with lowercase characters and special characters (Telex: Only 5-bit uppercase) * like Telefax, it transmitted formatted entire pages/documents ** however, Teletex transmits the text characters and their formatting (Telefax: A raster-pixel-image). Teletex was invented aroud 1981. German operation was from 1981 through 1993. h2. Terminal Devices 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. 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. {{child_pages()}} h2. Network 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. h2. Relevant Specifications * ITU-T F.200 (Teletex service) * ITU-T T.61 (Teletex character set) * ITU-T X.21 (interface)
