The Computek 300 is a graphics terminal from around 1972.
As quoted from “Computer Aided Design”, Volume 4 Number 5 October 1972:
The Computek 300 v.d.u, is intended for display of both alphanumeric and graphical data. Standard features of the terminal include a teletype compatible series interface and a refresh at 50 times/s to guarantee a flicker-free display. One thousand and fifty characters can be displayed on the 12 in screen and a large number of vectors of any length van be displayed on a 256 X 256 grid. Individual characters or vectors can be edited without the need to erase and rewrite the entire screen. A Fortran software package is supplied with each terminal to help the user interface his applications programs easily to the Computek 300. (Computer and Systems Engineering Ltd., Woodcock Hill Estate, Harefield Road, Rickmansworth, Hertfordsbire, WD3 1PL, England)
Trivia: Eindhoven University used a Computek 300 to communicate with the control system of their cyclotron.