| 摘要 |
This invention is directed to a communication system of the wired type and is especially suitable for use in emergency situations such as arise in the case of fire, or violence eruptions in cities. The system is adaptable for use with existing fire alarm loop-call systems as the substations of the system may readily replace the standard fire callboxes, i.e., they may be connected in series in existing fire callbox loops with many advantages being provided.
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