Editing Bildschirmtext

{{Short description|German videotex service}}
{{more citations needed|date=May 2022}}
{{Infobox online service
| name                         = Bildschirmtext
| title                        = Bildschirmtext
| logo                         = Bildschirmtext Logo.svg
| logo_size                    = 200px
| logo_alt                     =
| logo caption                 = Bildschirmtext on-screen logo
| image                        = 
| image_size                   =
| image_alt                    =
| caption                      = 
| developer                    = [[Systems Designers Ltd]], [[Deutsche Bundespost]]
| generation                   =
| type                         = [[Videotex]]
| launched                     = {{Start date and age|1983}} 
| discontinued                 = {{End date and age|2001}}
| version                      =
| version release date         =
| preview version              =
| preview version release date =
| updated                      =
| platform                     = [[CEPT1]] profile
| operating system             =
| status                       = Discontinued
| members                      = 
| website                      =
}}
[[File:BBildschirmtext reconstruction.png|thumb|Reconstruction of the Bildschirmtext welcomepage after login]]
[[Image:1987 German Youth standing next to BTX Terminal in German Post Office.jpg|thumb|1987 photo of a German youth standing next to a German Post Office Btx terminal]]
[[Image:Btx device.jpg|thumb|German "Multifunktionales Telefon 12"]]
[[File:Modem DBT-03.jpg|thumb|Modem for accessing the Bildschirmtext service]]
'''Bildschirmtext''' ([[German language|German]] "screen text", abbrev. '''Btx''' or '''BTX''') was an [[online service|online]] [[videotex]] system launched in [[West Germany]] in 1983 by the [[Deutsche Bundespost]], the (West) German [[mail|postal service]].<ref name="auto">{{cite news|url=https://www.spiegel.de/wirtschaft/bildschirmtext-computerwissen-fuer-alle-a-6dd9ba4b-0002-0001-0000-000014019866|title=Bildschirmtext - Computerwissen für alle?|newspaper=Der Spiegel |date=March 13, 1983|via=www.spiegel.de}}</ref>

Btx originally required special hardware (it was based on [[GEC 4000 series]] computers) which had to be bought or rented from the British [[General Post Office]]. The data was transmitted through the [[telephony|telephone network]] using [[ITU-T V.23|V.23]] [[modem]]s and the content was displayed on a [[television]] set.


==History==
Originally conceived to follow the UK [[Prestel]] specifications, and developed on contract by a small UK company called [[Systems Designers Ltd]] (originally merged into [[Electronic Data Systems|EDS]] and now part of [[Hewlett-Packard|HP]]) for [[IBM]] Germany. Btx added a number of additional features before launch, including some inspired by the French [[Minitel]] service, to create a new display standard of its own, which in 1981 was designated the [[CEPT1]] profile.<ref>{{cite web |last=ETSI Secretariat |date=November 1990 |title=Terminal Equipment (TE); Videotex presentation layer protocol Videotex presentation layer data syntax |url=https://www.etsi.org/deliver/etsi_i_ets/300001_300099/300072/01_60/ets_300072e01p.pdf}}</ref><ref name="auto1">{{cite web|url=http://bildschirmtext.btx-informationen.rehbein.net/|title=Bildschirmtext-Seite nach dem CEPT-Standard als GIF-Graphik wiedergegeben|website=bildschirmtext.btx-informationen.rehbein.net}}</ref><ref>{{cite web|url=https://artsandculture.google.com/asset/btx-page-overview-of-bildschirmtext/tgGo7M8lYU15rQ |title=BTX page "Overview of Bildschirmtext" — Google Arts & Culture |date= |accessdate=2022-05-23}}</ref> 

The system was presented at the IFA in [[Berlin]], with a trial system installed in [[Düsseldorf]] and Berlin in 1980.<ref name="auto"/><ref name="museum1">{{cite web |last=Museum for Communication Nuremberg |title="Bildschirmtext," a videotex system: A network before the Internet |url=https://artsandculture.google.com/story/mwVROPu6jgAeLA}}</ref>
In 1981, the system was expanded to rest of Germany, with the necessary network being developed by [[IBM]].<ref name="museum1"/>
The system was launched nationwide in 1983, at the press of a button by the Federal Post Minister at Berlin's IFA<ref name="museum1"/> The service could only be used with a modem produced by the Bundespost and user uptake was low.

The "MultiTel" devices could operate without a TV and allowed simultaneous telephone operation. By 1986, there were also adaptor devices for home computers like the [[Commodore 64]] (ex: Siemens Decoder Module II).<ref name="museum1"/> 

By the 1990s, the system was renamed "Datex-J" and focused on the home users.<ref name="museum1"/>

In 1995, an enhanced backward-compatible standard called Kernel for Intelligent Communication Terminals (KIT) was announced, but this never really gained acceptance. 
Btx formed the basis of [[T-Online]], Deutsche Telekom's online service, which maintained a Btx interface in its access software after the T-Online brand was introduced in 1995.

After [[German reunification]], Btx was available throughout [[Germany]]. Btx was also available in [[Austria]] and [[Switzerland]], where it was called ''Videotex''<!--sic--> (VTX).

The last Btx access was switched off at the end of 2001 by [[Deutsche Telekom]];<ref name="museum1"/> it had been made obsolete by the [[Internet]].

==Operation==
Btx permits the transmission of graphical pages with a resolution of 480 by 250 [[pixel]]s, where 32 out of a palette of 4096 colors could be shown at the same time.<ref name="auto1"/><ref>{{cite web|url=https://dcsutherland.smugmug.com/Other/Retrotechnology/Bildschirmtext-Btx-German/i-PBH9x3N/A|title=Bildschirmtext (Btx) German Videotex System - David|website=dcsutherland.smugmug.com}}</ref> Each page could display 40×24 [[semigraphic]] text characters.<ref name="auto"/> This corresponds to the technical possibilities of the early 1980s.

Btx always transferred whole screen pages; the receiver paid per received page. The content provider was free to set the price, and could require either a fee per page (0.01 [[German mark|DM]] to 9.99 DM), or a time-dependent fee (0.01 DM to 1.30 DM per minute).

Data was transferred [[Authenticated encryption|unauthenticated]] and in plaintext, leading to the [[Chaos Computer Club#BTX-Hack|BTX hack]] by [[Wau Holland]] in 1984.

== In Media ==
Bildschirmtext is referenced in the German language version of the song "[[Computer Love (Kraftwerk song)|Computerliebe]]" by Kraftwerk. The song's lyrics, "Ich wähl die Nummer, ich wähl die Nummer / Rufe Bildschirmtext, rufe Bildschirmtext" ("I call this number, I call this number / Call Bildschirmtext, call Bildschirmtext"), reference the service as it was in 1981.<ref>{{cite web |title=Kraftwerk - Computer Liebe Lyrics |url=https://genius.com/Kraftwerk-computerliebe-lyrics |website=Genius.com |access-date=24 December 2022}}</ref>

==References==
{{reflist}}

==External links==
{{commons category|BTX}}
* [https://web.archive.org/web/20080719075504/http://dcsutherland.smugmug.com/gallery/4125818 Screen Shots from Btx terminal displaying its description and history]
* [http://bildschirmtext.btx-informationen.rehbein.net Some example pages] {{in lang|de}}
* [http://www.spiegel.de/spiegel/print/d-14019866.html Bildschirmtext: Computing for all?], ''[[Der Spiegel]]'', 14 March 1983. {{in lang|de}}  Article on the launch of the system.

{{Videotex}}

[[Category:Computer-related introductions in 1983]]
[[Category:History of telecommunications in Germany]]
[[Category:Videotex]]
[[Category:Deutsche Telekom]]