Obsolete Sounds: collection of disappearing sounds and extinct sounds
I wish I had been able to sneak good stereo recorder into a 1A ESS telephone switch. These had electronic computerized control, but the call-path was all electromechanical, and the sound of relays opening and closing all around was otherworldly. A typical ESS machine might occupy several thousand square feet, so you could walk through it and hear the activity all around you.<p>During the day when call volumes were high, it was cacophony. I&#x27;ve heard it called a &quot;typewriter factory&quot;, just a blur of clicking and clacking.<p>But at night, as the call volume slowed, you could pick out individual calls. A line-relay here as someone goes off-hook, no more sound while they dial (most everyone was touch-tone by this time), but as soon as the control interprets the digits and determines a call path, it&#x27;s time to set up the path! Junctor frames for some reason had much larger relays, and several of these would fire in rapid succession, followed by a smattering of other relays between the line equipment, the junctor, and some other frames I don&#x27;t remember.<p>If you stood in the right place, you could hear the progress of the call as it physically rippled across the machine, each section of the path first switching to a test circuit to make sure it was healthy, then on to the actual circuit, giving and odd staccato double-click sound to each action. Once the call was over, everything would tear down, and all the relays would relax at once.<p>It&#x27;s one of the most magical sonic environments I&#x27;ve ever been in, and I&#x27;ve never gotten to share it with anyone.