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US4621358A
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Remote switch for telephony switching system
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US4573151A
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Interface unit for telephone system having remote units
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Voltage regulation circuit
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Digital tone signal generator for telephony system
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US4479034A
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Arrangement of interactive processors for control of ports
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CA1166728A
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Fault monitoring and diagnostic system for telephony switching system
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US4430530A
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Telephony system with automatic test call generator for remote port groups
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US4555595A
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Sampled port data switching system employing interactive processors
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US4523308A
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Telephone concentrator switch arrangement
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US4471169A
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Arrangement of interactive telephone switching processors and associated port data storage means
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US4443663A
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Filtering of port data in a switching system employing interactive processors
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US4451703A
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All electronic interface for telephony system
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US4437096A
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Concentrator circuit incorporating solid state bilateral bridge arrangement
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CA1173942A
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Maintenance processing apparatus for remote port units in a telephone switching system
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US4387278A
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Maintenance facility for telephony system with remote port groups
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CA1181158A
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Telephony system with automatic test call generator for remote port groups
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US4447673A
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Ring trip apparatus for a line circuit connected to DCO switch
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US4451702A
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Arrangement of interactive telephone switching processors for performing timing analyses of port events
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US4385206A
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Programmable port sense and control signal preprocessor for a central office switching system
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US4393495A
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Message translation arrangement for telephony system with romote port groups
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