Bildschirmtext

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Bildschirmtext (German "screen text", abbrev. Btx) was a V.23 online service launched in West Germany in 1983 by the Deutsche Bundespost, the (West) German postal service. Btx originally required special hardware, which had to be bought or rented at the post office. The data was transmitted through the telephone network and the content was displayed on a television set.

Like the French Minitel, Btx originally used the CEPT standard. Later it was switched to the backward-compatible KIT standard, which however never really became accepted. CEPT permits the transmission of graphical pages with a resolution of 480 by 250 pixels, where 32 out of a palette of 4096 colors could be shown at the same time. This corresponds to the technical possibilities of the early 80's.

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 DM to 9.99), or a time-dependent fee (0.01 DM to 1.30 DM per minute).

The last Btx access was switched off at the end of 2001 by Deutsche Telekom; it had been made obsolete by the Internet. However, 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 (VTX).