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US4922516A
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Telephone technician's terminals with auto-selection of dial pulse on DTMF signalling
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US4837811A
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Telephone technician's terminals
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US4167682A
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Overshoot suppression circuitry for ternary pulses
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US4095058A
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Telephone switching system test set
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US4070646A
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Pulse error detector
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US4022987A
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Coin telephone station simulator and condition indicator
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US3992699A
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First-in/first-out data storage system
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US3906162A
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Loop extender with bypass capacitor discharge
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CA1024678A
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Voltage and current-sensitive loop extender
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CA1005936A
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Active shunt impedance for compensating impedance of transmission line
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US3898389A
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Voltage and/or current-sensitive loop extender
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US3894284A
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Current flow test apparatus
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US3875346A
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Revertive pulsing
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US3863034A
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Translator alarm
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US3863032A
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Translator alarm
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US3814867A
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Active shunt impedance for compensating impedance of transmission line
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US3845253A
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Interconnecting assembly
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US3792205A
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Hand held telephone test instrument
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