Lear-Siegler ADM-3A

The LSI ADM-3A is a video display terminal introduced in 1976 by Lear Siegler, Inc. at a price of $1045 and designed with cost-effective TTL logic on a single circuit board and a 12-inch monochrome CRT capable of displaying 24 lines of 80 characters. It supported a RS-232 serial interface and offered cursor movement through control codes, which enabled more efficient screen editing compared to earlier models. Configuration was handled via onboard DIP switches, and models were available in assembled or kit form. The ADM-3A was used with early minicomputers and microcomputers, including the SWTPC 6800, as a terminal for command-line interaction and program development. Read more about the ADM-3A terminal restoration.

Lear Siegler Incorporated was formed in 1962 through the merger of Siegler Corporation, a diversified conglomerate originally based in Illinois but relocated to Southern California, and Lear, Inc., an aerospace electronics firm founded by William Lear, who later went on to develop the Learjet. The combined company, headquartered in the Los Angeles area during the 1970s, became a prominent player in aerospace, defense, and industrial electronics, producing everything from avionics to computer terminals like the ADM-3A.