Office line connection circuit during service interruptions in key telephone apparatus
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United States of America Patent
Stats
-
Apr 7, 1981
Grant Date -
N/A
app pub date -
Jan 30, 1979
filing date -
May 2, 1978
priority date (Note) -
Expired
status (Latency Note)
Importance
Abstract
A switching matrix in the key service unit of a key telephone system is formed by several groups of relays, each group being associated with a particular station set and each relay in each group also being associated with a particular central office line. All of the relays, except one in each group, disconnect the associated station set from the associated line when the relay is de-energized. One relay in each group functions in the opposite manner to connect the associated station set to the associated line upon failure of the local power supply.
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