BildTel 001 » History » Revision 25
Revision 24 (laforge, 12/29/2023 12:54 PM) → Revision 25/27 (laforge, 12/29/2023 12:55 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)
The specific unit I managed to acquire has been with the "Hochschule für Telekommunikation Leipzig (HfTL)":https://de.wikipedia.org/wiki/Hochschule_f%C3%BCr_Telekommunikation_Leipzig until its closure in 2022.
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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The Codec unit ("Bildeinheit") consists of a variety of different circuit boards:
* 1x power supply
* 4x "mainboards" stacked on top of each other (two sandwiches of two PCBA)
** top two boards (CODER / DECODER) have a number of DIN 41612 slots for plug-in cards
* 6x CODEC ADSP boards plugged into slots of the CODER
* 3x CODEC ADSP boards plugged into slots of the DECODER
* 1x OUTDIG/OUTANA sandwich, consisting of two PCBA plugged into slots of the DECODER mainboard
** this is the TV output board, generating and digital-analog-converting analog TV signal
* 1x INDIG/INANA sandwich, consisting of two PCBA plugged into slots of the CODER mainboard
** this is the camera input board, receiving and digitizing the analog TV camera signal
h4. AEG-OLYMPIA CODEC ADSP
This board exists 9 times in total (6x for CODER, 3x for DECODER). It hosts a digital signal processor, RAM and some FIFOs.
There are no visible differences between the boards; also the label on the GAL is identical.
PCB Marking: @1601914L11T@
Connector Marking: None
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|ADI ADSP-2101|Digital Signal Processor|
|VX-8111 10.0000 MHz|Crystal Oscillator|
|GAL20V8A (4012-001/2)|GAL|
|2x IDT 7201SA25J|FIFO|
|2x IDT 7202SA25J|FIFO|
|3xCY7C199-45VC|RAM|
* GAL image: attachment:bildtel001-aeg_olympia_codec_adsp_4012-001_2_GAL20V8A.jed
h4. AEG-OLYMPIA OUTDIG
PCB Marking: @2401913L1T@
Connector Marking: @35.103-3030.2 SN. 3051@
top PCBA:
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|Brooktree Bt101|Triple 8-bit VIDEODAC|
|Xilinx XC2018-100|FPGA 100 CLBs, 1000 Gates|
|S-Data SXO-300C 27.00000 MHz|Crystal Oscillator|
|3x IDT 7201SA25J|FIFO|
h4. AEG-OLYOMPIA OUTANA
TBD
h4. AEG-OLYMPIA INANA
This is the analog input board.
PCB Marking: @0202914L1T@
Connector Marking: @35.103-3023.8/01@
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h4. AEG-OLYMPIA INDIG
This is the digital input board, containing the video ADC and support circuitry
PCB Marking: @0202915L1T@
Connector Marking: @35.103-3020.2/01@
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|Brooktree Bt253KPJ|Color Video ADC|
|Xilinx XC3030-70|FPGA|
|DOC31CC 27.000M|Crystal Oscillator|
|3x TI TLC272CP|OpAmp; likely buffers for analog R/G/B|
|0900-002/2|SPI flash for FPGA bitstream?|
|3x QSL QS8201-15JR|512x9 FIFO|
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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* EPROM image: attachment:bildtel001_keyboard_74E84.251U22g_1.0.0_010389_M2764A.bin
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. History
The information below is based on a 2023 conversation between Harald Welte and Roland Gaidzik (project manager of the AEG-OlYMPIA Video Phone).
Prior to the _Bildtel 001_, there was a research project by Daimler-Benz in Ulm, who developed the codec and created a much larger prototype using a VME-bus computer.
The task of the AEG-Olympia (by then also already a Daimler subsidiary) was to translate that research into an actual product that can be produced and sold. The result was the _Bildtel 001_.
* More than 100 units (possibly multiple hundreds, but certainly less than 1000 units) were built.
** Most of them were purchased by Bundespost
** a few were given as loner/rental devices
** probably less than 10 were ever sold directly by AEG-Olympia to other custmers
* Stollmann (in Hamburg) was responsible for building all the electronics (of the video/codec unit)
* The ISDN call control and user interface handling was developed by AEG-Olympia in Konstanz
** 4 people working in Marketing for the product
** 7 people working on R&D
* Actual assembly of te final product happened at the AEG-Olympia factory in Wilhelmshaven
* Testing/approvals done at a FTZ Facility
* The Codec part (even for the final product) was still provided by the research team in Ulm
* It is expected/assumed, that the Bildtel 001 already implements the ITU-T H.320 standards, as there was strong desire for this by Bundespost
* The _LOEWE MultiTel TV10_ is used almost without modifications. Only very minor softare modifications were made
** It is not expected that the actual BTX/CEPT decoder is used in the product. The UI is generated by the codec unit and presented as analog RGB on the SCART to the TV
** The BTX/CEPT decoder likely simply passes through the keyboard input to the V.24 interface towards the codec unit
* The power supply was a standard industrial power supply bought on the market
* The video camera was a standard part bought on the market
As AEG-Olympia went out of business and shut down, the responsibility of the _Bildtel 001_ was passed on to Dornier (back then also another subsidiary of Daimler-Benz). Apparently the Bundespost was very much encouraging Daimer-Benz to keep that project alive and not let it die together with AEG-Oympia.
h3. Use in _Piazza Virtuale_ project of _Van Gogh TV_
In 1992 there was an interactive TV project _Piazza virtuale_ done by _Van Gogh TV_, an artist and hacker collective. They pioneered interactive television and aspects of social networks more than a decade before this became possible for people on the Internet. As part of this project, they were using Bidltel 001 phones to transmit audio+video from remote studios to the main TV studio.
You can find the following related documents/resources:
* "a website documenting the overall project":https://vangoghtv.hs-mainz.de/
* "a document showing signed receipts for video telephony equipment, including Bildtel 001":https://vangoghtv.hs-mainz.de/wp-content/uploads/2021/04/picture-phone-reciepts.pdf
* "a reference to both analog slow-scan TV as well as ISDN picture phones" at https://vangoghtv.hs-mainz.de/?portfolio=einsatz-von-slow-scan-tv-und-isdn-bildtelefonen
* "interviews with the creators of the project":https://vangoghtv.hs-mainz.de/?page_id=86921
* "an example TV programme whose content was apparently transmitted via Bildtel 001 from Zurich to the TV studio":https://www.youtube.com/watch?v=bZ0WwvG_Pt8&list=PLDUukqMXwk2wJJZM9JhEGoDmx9PX2VTOk&index=24
h2. Further Reading
* "Thread on the fediverse covering the BildTel 001":https://chaos.social/@LaF0rge/111317641831468838
