CMS:Number Three Electronic Switching System

This page is about specific switch in the Connections Museum. For the switch in general, see Number Three Electronic Switching System.

The 3ESS at the Connections Museum while running

Volunteers æstrid and Colin working on the 3ESS using an oscilloscope and a logic analyzer.

The Number Three Electronic Switching System (3ESS) is an electronic switching system on the second floor of the Connections Museum. It was originally installed in 1978 as a Community Dial Office (CDO) in the village of Crosby, Washington. It contains a custom tape drive emulator created by volunteers at the museum after the original tapes began to fail.