Full Mechanical: The Panel Telephone Switch
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How does a No. 1 Crossbar work? - Dial Equipment Appreciation, Part 2
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All calls are failing in the Panel office!
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東海総合通信局のイメージする不法無線局・違法無線局の人はコレらしい
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The 5XB Trouble Recorder
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What happens if you leave your phone off the hook?
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AT&T Archives: The Step-By-Step Switch
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The Machine that Makes Your Phone Ring
23:18