TitleIBM 1720 SMS mercury-wetted switches
ManufacturerInternational Business Machines Corporation (IBM)
|Other number||396975||Printed on bottom of board.|
|Other number||804||Engraved on top of board|
|Other number||ERK 374494||Engraved on top of board|
|Other number||XE07||Handwritten on top of board|
Dimensionsoverall: 1/4 in x 4 1/2 in x 2 5/8 in
DescriptionWritten on a scrap of paper next to board was "79.80."
Letter in paper file excerpt, "They are switches from the 1720, a prototype of IBM's first entry into process control systems. The 1720 was installed at three test locations in 1959 and 1960; The AMOCO refinery in Whiting, Indiana, an acrylo-nitrile pilot plant of DuPont in Wilmington, Delaware, and at the Standard Oil Refinery in El Segundo, California. The 1920 prototype system was followed by the 1710 and 1800 products in the 1960s."