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BildTel 001 » History » Revision 19

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laforge, 10/30/2023 08:48 PM


BildTel 001

The Telekom-branded BildTel 001 was likely the first commercially available ISDN video phone in Germany.

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isdn-bildtelefon-picture-alliance-zb-matthias-hiekel-11764519.jpg
(Only digital marketing picture I could find online, courtesy of Picture Allianze / Matthias Hiekel)

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

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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)
    • boards have a number of DIN 41612 slots for plug-in cards
  • 9x CODEC ADSP boards plugged into slots of the top two mainboards
  • 1x OUTDIG sandwich, consisting of two PCBA plugged into slots of the top mainboard
    • this is the TV output board, generating and digital-analog-converting analog TV signal
  • 1x FIXME sandwich, consisting of two PCBA plugged into slots of a 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. 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

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

bottom PCBA: FIXME

AEG-OLYMPIA INANA

This is the analog input board.

PCB Marking: 0202914L1T
Connector Marking: 35.103-3023.8/01

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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

TV Camera

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TV / BTX Unit

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BTX decoder

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: 20231029_093033.jpg

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)

Further Reading

Updated by laforge 8 months ago · 19 revisions

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