BildTel 001 » History » Revision 11
Revision 10 (laforge, 10/30/2023 08:10 PM) → Revision 11/27 (laforge, 10/30/2023 08:11 PM)
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h1. BildTel 001
The Telekom-branded *BildTel 001* was likely the first commercially available ISDN video phone in Germany.
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(Only digital marketing picture I could find online, courtesy of Picture Allianze / Matthias Hiekel)
h2. Architecture
The system consists of the following parts:
* A TV screen with built-in [[BTX__Prestel__Videotex__Minitel|BTX]] decoder (inherited from [[LOEWE_Multitel_TV10]])
* A keyboard + phone-receiver combo (inherited from [[LOEWE_Multitel_TV10]])
* A _desktop-computer-like_ box called the Codec (containing the actual ISDN video telephony part, implemented by AEG/OLYMPIA)
* A video camera
The BTX Terminal [[LOEWE_Multitel_TV10]] was used as the "user interface" for the device, adding the _codec_ box to turn it into a video phone.
h3. Codec unit
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h3. TV Camera
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h3. TV / BTX Unit
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h4. BTX decoder
* EPROM image: attachment:bildtel001_tv10_btxdecoder_16772_074_349_27C010.bin
h3. Keyboard/receiver unit
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Actual Cherry keyboard PCBA after full disassembly, ultrasonic cleaning of all keycaps and lots of isopropanol on the PCB, removing what might be decades old coke residue:
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h2. Connections
h3. Codec unit
* connects to ISDN basic-rate S0 interface using 8P8C/RJ45 plug
* has two proprietary connectors for attaching video cameras
* has two SCART connectors (one for audio/video output to the TV)
* has a TAE jack for attaching an analog phone for the audio port (connected to the combined keyboard/receiver unit by default)
* has another TAE jack (purpose unknown)
* has a V.24 interface on a SUB-D 9 connector which connects to the built-in BTX decoder of the TV unit
h3. TV Camera
* connects to the Codec unit using a proprietary high-density connector that appears to carry both video and power
h3. TV unit
* has an RF input for TV broadcast signals (PAL)
* has a SCART input for baseband audio/video from peripherals (like the Codec unit)
* has a DIN speaker output for attaching an external speaker
* has a built-in BTX decoder with
** an unused DIN port intended to connect to the [[DBT-03]] BTX-Modem (not used in the ISDN video application)
** an unused centronics port
** an auxiliary V.24 port on a DIN connector interfacing the SUB-D 9 of the Codec unit
h3. Keyboard/receiver unit
* has a cable with TAE connector attached (connects to codec unit)
h2. Further Reading
* "Thread on the fediverse covering the BildTel 001":https://chaos.social/@LaF0rge/111317641831468838
