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laforge, 11/13/2023 02:16 PM
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- BildTel 001
BildTel 001¶
The Telekom-branded BildTel 001 was likely the first commercially available ISDN video phone in Germany.
(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 until its closure in 2022.
Architecture¶
The system consists of the following parts:- A TV screen with built-in 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.
Codec unit¶
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
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
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 |
AEG-OLYMPIA OUTDIG¶
PCB Marking: 2401913L1T
Connector Marking: 35.103-3030.2 SN. 3051
top PCBA:
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 |
AEG-OLYOMPIA OUTANA¶
TBD
AEG-OLYMPIA INANA¶
This is the analog input board.
PCB Marking: 0202914L1T
Connector Marking: 35.103-3023.8/01
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
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 |
TV Camera¶
TV / BTX Unit¶
BTX decoder¶
- EPROM image: bildtel001_tv10_btxdecoder_16772_074_349_27C010.bin
Keyboard/receiver unit¶
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:
Connections¶
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
TV Camera¶
- connects to the Codec unit using a proprietary high-density connector that appears to carry both video and power
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
Keyboard/receiver unit¶
- has a cable with TAE connector attached (connects to codec unit)
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 peopel 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 camere 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.
Further Reading¶
Updated by laforge 8 months ago · 21 revisions