LA50

A dot matrix printer is an impact printer that prints using a fixed number of pins or wires. The New York Times referred to them as "dot-matrix impact printers."

By contrast, other printing technologies for printing dot matrix output and thereby implementing non-impact dot matrix printing include:

Although nearly all of these alternative technologies print closely spaced dots rather than continuous lines or characters, it is not customary to call them dot matrix printers.

The first impact dot matrix printer was the Centronics 101. Introduced in 1970, it led to the design of the parallel electrical interface that was to become standard on most printers until it being displaced well over a decade later by the Universal Serial Bus (USB).

Digital Equipment Corporation (DEC) was another major vendor, albeit with a focus on use with their PDP minicomputer line. Their LA30 30 character/second (CPS) dot matrix printer was also introduced in 1970, the first of many.

Unlike the LA30's 80 column, uppercase-only 5x7 dot matrix, DEC's product line grew.

The DECwriter LA30 was a 30 character/second dot matrix printing terminal introduced in 1970 by Digital Equipment Corporation (DEC) of Maynard, Massachusetts

It printed 80 columns of uppercase-only 7×5 dot matrix characters across a unique-sized paper. The printhead was driven by a stepper motor and the paper was advanced by a noisy solenoid ratchet drive. The LA30 was available with both a parallel interface (LA30-P) and a serial interface (LA30-S); however, the serial LA30 required the use of fill characters during the carriage-return. In 1972, a receive-only variation named LA30A became available as well.

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Wikipedia