| 摘要 |
A line circuit for connecting an individual telephone line to a telephone switching network includes a dual coil line relay and a cutoff relay arranged in a balanced line configuration. Under normal off hook conditions, both the line and cutoff relays are operated. In a lockout condition the cutoff relay reminas operated through the off hook telephone. A monitor arrangement is provided for identifying the groups of line circuits that include a line circuit in lockout, for identifying the individual line circuits in lockout, and for providing an alarm signal when a preset number of line circuits are in lockout.
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