A. CONVENTIONAL FIRE ALARM SYSTEM

 A.K.A  “point wired” fire alarm system. One or more circuits are routed through the protected spaces or building. Along each circuit one or more detection devices are placed
System is often the natural choice for smaller system. Conventional type monitors the condition of each circuit by sending a small current through the wire. Should a fault occur, such as due to wire break, this current can not proceed and is registered as “trouble” condition.
In a conventional alarm system, all alarm initiating and signaling is accomplished by the system's hardware which includes multiple sets of wire, various closing and opening relays, and assorted diodes. Because of this arrangement, these systems are actually monitoring and controlling circuits, and not individual devices. 
The disadvantage is that Emergency responding personnel may need to search the entire zone to determine where the device is reporting a fire. Where zones have several rooms, or concealed spaces, this response can be time consuming and wasteful of valuable response opportunity.
Conventional systems may also be inherently labor intensive and expensive to maintain. Each detection device may require some form of operational test to verify it is in working condition. Smoke detectors must be periodically removed, cleaned, and recalibrated to prevent improper operation.
With a conventional system, there is no accurate way of determining which detectors are in need of servicing. Consequently, each detector must be removed and serviced, which can be a time consuming, labor intensive, and costly endeavor. If a fault occurs, the "trouble" indication only states that the circuit has failed, but does not specifically state where the problem is occurring. Subsequently, technicians must survey the entire circuit to identify the problem.