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Strowger Sounds

Started by Keelan, July 22, 2010, 10:26:25 PM

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Keelan

This is a partial re-post from the TCI list, but I wanted to "spread the word" about 'switching' on this forum.

I recently had a chance to make some recordings of my Ericsson PABX, a 50 line British Strowger switch, with 4000 style connectors.

A quick note on selector types and british nomenclature: the AE design that was ubiquitous in North America is known as "pre-2000" by our British friends. Not content with a design that came from across the Atlantic, they hatched the "2000" series mechanism. This design was the most successful in that country, and most exchanges and PBXes were built on this technology. The basic operation of vertical and rotary movement across a bank of 100 contacts remained the same, the fundamental difference being when it when it came time for the switch to reset at the end of a call. An AE style switch has a spring that pulls the wipers backwards across the contacts perviously stepped over, followed by gravity dropping the wiper assembly back to the lowest position. Upon release, a 2000 series selector steps the wipers forward across the bank of contacts, with gravity and a spring completing the release. At some point, the British Post Office hatched a new design known as the "4000" series selector, that was notoriously unreliable and prone to self-destruction. The 4000 series differed from the 2000 series in that the release followed the same pattern as used in AE mechanisms.

Anyway, enough of me yammering on. Here's what you hear on the telephone:

http://verticaloffnormal.org/files/Keelan's%20Collection/Switching/Ericsson%2010+50%20PABX/telephoneaudio.mp3

And this is what the PABX sounds like operating:

http://verticaloffnormal.org/files/Keelan's%20Collection/Switching/Ericsson%2010+50%20PABX/switchsounds.mp3

baldopeacock

"At some point, the British Post Office hatched a new design known as the "4000" series selector, that was notoriously unreliable and prone to self-destruction."

Joseph Lucas have a hand in that?