Adm computer

Did you know each time you visit the Old-computers home page, you see a Lear-Siegler ADM-3A terminal. displaying a READY message and a blinking cursor.

The ADM-3A was one of the first affordable serial display terminals manufactered by Lear-Siegler, Inc of Anaheim California.

Why ADM? Nobody knows, maybe American Dream Machine or Awful Dumb Monitor or Advanced Display Module or, more seriously, Anaheim Division, Manufacturing.

Why 3A? We know. Because this version quickly replaced a previous one, called ADM-3, which only displayed upper-case letters. The 3A version did not display upper-case letters, but an optional chip set allows them to be displayed

The product was originally sold in assembled form for $1,195. A kit version would appear few months

later, at $995. It could be ordered with a white, green, or amber tube background colour.

The ADM-3A quickly met with great success thanks to its reliability and low price.

Some models were also manufactured with a graphics add-on card of about the same size as its motherboard. With that card installed, the terminal emulated Tectronix 4014 graphics quite well.

The setup of this 'Dumb machine' (as Lear Siegler advertised) was done using. 32 dip switches (!) located at the left of the keyboard. Among them, 11 was used for the communication rate (from 75 to 19200 bauds), others for parity, display configuration, character set, etc.

Thanks to Sebastien Richter and his website for the system image.


Category: Computers

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