Volker-Craig/NABU 4404 Video Display Terminal

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Volker-Craig/NABU 4404 Video Display Terminal


computer hardware: video display terminal


Historical Context:

In the 1950s, the operators of mainframe computers used dedicated consoles, hardcopy terminals (such as teletypes and modified electric typewriters), and a variety of cathode ray tube (CRT) displays to run and control data processing tasks. Computer consoles typically featured rows of switches and associated lights that allowed operators to run and control the execution of programs, analyze data stored in memory, and to control other hardware interfaced with computers. Hardcopy terminals were used to print on roles of paper information such as operator's commands, computer responses, and other console messages. Finally, CRTs were used to displaying information (e.g. memory contents) in a rudimentary graphical form. The "glass teletype" that appeared in the mid-1960s was the first attempt at providing a single device allowing computer operators to run their systems having all the essential control and data processing information displayed on a screen. However, it was not until the early 1970s, when the first "dumb" video display terminals, featuring limited editing capabilities, were introduced (one of the earliest such terminals was the 7700A Interactive Display Terminal introduced by Lear Siegler Inc. in 1973). All these terminals shared the same basic keyboard-display-interface design: each featured a keyboard, a CRT screen that could display full sets of alphanumeric characters, and each had the capability to send and receive data via communication lines to a remote host computer. By the mid-1970s, video terminals became the most effective human-computer interface devices and they remain so until the mid-1980s, when they were displaced by microcomputers that could be interfaced with mainframes and minicomputers to perform terminal jobs in addition to microcomputing tasks, when PC monitors had become a common occurrence worldwide.

In Canada, the design and manufacturing of computer display terminals began in the early 1970s. Comterm Inc. (Montreal), Cybernex Ltd. (Ottawa), Electrohome (Kitchener), Lektromedia (Pointe Claire), NORPAK (Kanata), TIL Systems Ltd (Toronto), and Volker-Craig (Waterloo) were some of the pioneering companies.

Volker-Craig Ltd. was a Canadian manufacturer of video display terminals, founded in 1973 by Michael C. Volker and Ronald G. Craig, both graduates from University of Waterloo. The company's early objective was to manufacture inexpensive video terminals. In a 2020 interview by Steven Forth for Ibbaka market blog, Volker recollects that

"In those days... video displays were very, very expensive and being a student, I thought, this [video terminal manufacturing] needs to be done in a way that is economical for students."

Volker's fourth-year engineering project to design an electronic circuitry for a video terminal that would allow the presentation of characters on the screen of a rudimentary television set was an entrepreneurial trigger. By the end of the 1970s, Volker-Craig was selling its terminals around the world through its offices and distributors in, among other countries, Argentina, Austria, Australia, Belgium, Canada, Denmark, Finland, France, Germany, Hong Kong, Ireland, Israel, Italy, Japan, Korea, Mexico, The Netherlands, New Zealand, Norway, Philippines, Singapore, Spain, Sweden, Switzerland, Taiwan, UK, and US.

In January 1982, Volker-Craig merged with five other companies to form NABU Manufacturing Ltd. with headquarters in Ottawa, and continued to develop video terminals. In 1984, as a result of NABU's restructuring, Volker-Craig became once again a fully independent company renamed as Volker-Craig Technologies Ltd.

In 1982, Volker-Craig introduced the VC4404 display terminal -- the Chat. It was a low cost stand-alone, ASCII, serial asynchronous computer peripheral that could be connected to any computer equipped with an RSC232C interface. The terminal offered comptibilty with the company's popular VC404 and the Lear Siegler ADM-3A -- an influential early video display terminal.

VC4404 technical specifications:
  • CPU: Zilog Z80A
  • display: 12" anti-glare, 24 lines, 80 characters per line, normal or revers video, character highlighting
  • keyboard: detachable, QWERTY, upper/lower case characters, 10 program function keys, 8 switches to control the screen display
  • ports: EIA RS232C communications interface
  • data rates: from 110 up to 19200 baud
  • options: serial and parallel interfaces, numeric key-pad and function keys, APL character set, ccoloured anti-glare display screen (amber or green)

NABU 4404 documentation:

  • VOLKER-CRAIG User's Manual, VC4404 The CHAT Video Display Terminal, Volker-Craig/NABU, Rev. 3, March 1982,
  • VC4404 Video Display Terminal, Service Manual, Volker-Craig, 1982,
  • VOLKER-CRAIG VC4602 User Manual, Volker-Craig, 1982

The museum has a VC4404 terminal and the above mentioned documentation.






NABU Collection




Volker-Craig , “Volker-Craig/NABU 4404 Video Display Terminal,” York University Computer Museum Canada, accessed May 27, 2023, https://museum.eecs.yorku.ca/items/show/301.

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