Lear Siegler ADM-3A

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The Lear Siegler ADM-3A was a very popular early video terminal; its low price (US$955), compared to its competitors, made it a common choice. The "ADM" part of the name reputedly stood for 'American Dream Machine'.

It was implemented entirely in discrete gates (TTL family); this was long before the era of microprocessors, or any other programmable technology.

The -3A was based on an earlier model, the -3, which initially only supported upper-case, and displayed 12x80 characters; options for lower-case, and 24x80 display, were later made available. The -3A differed in supporting the ability to set the cursor to any screen location, making use with video editors possible.

Later retrofit

Zentec produced a retrofit card which replaced the very large original PCB of the ADM-3A with a much smaller card using the NS405 Terminal Management Processor chip.

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