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some old technology

We were driving home and stopped in Auburn CA for lunch.

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Towns used to have red fire alarm boxes here and there. One opened a door and pulled a lever. That wound up a clockwork mechanism that turned a gear with teeth cut out, which made a series of pulses, typically a 2-digit code. A bell would ring in the fire station, hence the Bell code chart. Bing-bing-pause-bing was code 21. It would repeat until the clockwork ran down. The circuit was called a McCullough Loop.

I once designed and sold a little potted module, with dip switches, to replace the old rusty clockwork things.

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John Larkin      Highland Technology, Inc 

The best designs are necessarily accidental.
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jlarkin
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Boston still has a small team that maintains the telegraph-based system; there are about 1,200 boxes in the city proper. They're rugged devices and not very high-maintenance. It's considered "cheap insurance" and is thought to have saved perhaps a dozen lives over the past decade responding quickly to fires that would've otherwise taken longer to report due to phone or cellular outages

Reply to
bitrex

They removed the Federal Signal air raid siren that was mounted to a telephone pole across the street from the house I grew up in sometime in the early 1990s. Don't recall it ever being used for anything thankfully

Reply to
bitrex

The original design and development was described in detail in an issue of "ITT Electrical Communications" some time in the late 1920s or early

1930s (sorry I can't be more specific). You can download copies from worldradiohistory.com 
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~ Liz Tuddenham ~ 
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Liz Tuddenham

We had a fire siren on our corner, was removed in the late 90's, early 2000' as well. As dog owners, we found it interesting the dogs did not bark at the siren's like most others. If they grow up around a siren they get accustom to them.

Cheers

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Reply to
Martin Rid

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