• Table of contents
• BildTel 001
  • Architecture
    • Codec unit
      • AEG-OLYMPIA CODEC ADSP
      • AEG-OLYMPIA OUTDIG
      • AEG-OLYOMPIA OUTANA
      • AEG-OLYMPIA INANA
      • AEG-OLYMPIA INDIG
    • TV Camera
    • TV / BTX Unit
      • BTX decoder
    • Keyboard/receiver unit
  • Connections
    • Codec unit
    • TV Camera
    • TV unit
    • Keyboard/receiver unit
  • History
  • Further Reading

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

• GAL image: bildtel001-aeg_olympia_codec_adsp_4012-001_2_GAL20V8A.jed

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:

• EPROM image: bildtel001_keyboard_74E84.251U22g_1.0.0_010389_M2764A.bin

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 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.

Further Reading¶

• Thread on the fediverse covering the BildTel 001