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.

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.

Dennis J. Cagan, co-inventor of this the ADM-3A terminal, reports :

I just spotted your site when searching for some info on someone. I noticed a Lear Siegler ADM-3A video display terminal on your masthead. Seeing the unit was a thrill. I was one of the co-inventors of the device - it was intended to stand for American Dream Machine. It replaced the LSI 7700A. The ADM-3 itself listed for $1500 originally.

I was the regional sales manager for LSI and sold over 90% of the units sold worldwide from '73-75. I still have the gold ATMOS clock with a plaque to prove it. The other 3 inventors were engineers. We all I left LSI in '75 and started SOROC Technology (the only sign of which is a spin off in Canada www.soroc.com).

The first product from SOROC was actually a design for a product similar to the ADM which we sold to Beehive and it became the B100 in '76-77.