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dec 30, 1887 - Hammond V. Hayes

Description:

Common battery system developed by Hammond V. Hayes, allows one central battery to power all telephones on an exchange, rather than relying on each units own battery.

Added to timeline:

click for descriptions/PHONE TIMLINE

ByJasun Foley
23 Oct 2018
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431

Date:

dec 30, 1887
Now
~ 138 years ago
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