1. Telephone trial at 5 Exeter Place

    · 5 Exeter Place, Boston, Massachusetts, United States

    Telephone trial at 5 Exeter Place
    Wikimedia Commons · Public domain · file

    Bell and Thomas Watson tested paired membrane devices over a line between rooms in Bell's Boston residence. The source says the test occurred a few days after July 1, 1875; date precision is therefore limited to July.

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