Computer Operations CO-4420 Serial Box  
Written by Accutron on 2012-05-22  

The Computer Operations CO-4420 Serial Box is a ruggedized portable ASR computer terminal with an integral LINCtape / DECtape style drive, housed in a Halliburton Zero Centurion Elite suitcase. The CO-4420 supports RS-232 and current loop interfaces, and features a one-line 40-character alphanumeric VFD. Computer Operations also manufactured the CO-4410, which omits the display and keyboard featured in the CO-4420.

Computer Operations is best known among computer historians for their range of LINCtape drives, widely used in the 1960s with DEC and Data General systems. The CO-600 is the most iconic model, featuring dual 'upside down smiley face' drives, the same configuration that was used with the original LINC computer. The Serial Box pictured here features an alternate drive configuration, with a distinctive S-shaped tape guide. This style of drive was also available as a rack-mount peripheral (CO-1005T) for use with contemporaneous minicomputer systems.

Given the late 1970s production timeframe, it's likely that the CO-4420 is one of the last implementations of the LINC tape drive ever produced. The unit pictured here was manufactured in 1980, and is currently the only known example of a CO-4420 system still in existence.

Computer Operations CO-4420 Serial Box ruggedized terminal, serial number 4207.

CO-4420 Serial Box, enlargement of Western Magnetics 10-track tape head. The LINCtape standard specifies two redundant sets of five tracks on a 0.75" tape.

Two press releases for the CO-4410 and CO-4420 Serial Box, published in Computerworld magazine, September 12 1977 and November 13 1978, respectively. Note the substantially different design of the CO-4420 pictured in the release, as well as the disparity in advertised tape drive capacity.

This article is part of the [Digital Computer Equipment] exhibit.

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