Do you want to use the DC24V of the alarm system for the power cord of the bus-specific fire-fighting telephone?
I have not seen the telephone extension to use 24V power supply, are generally by the fire center bus phone host pull two pairs of lines to the bus phone module (two pairs of lines are the telephone audio line and telephone bus), and then from the phone module Pull a pair of lines to the telephone extension (this line for the telephone audio line).
1, the bus system of the fire telephone extension or telephone jack is no need for external power supply, through the fire telephone bus directly access the fire telephone controller. But the fire telephone controller (usually with the alarm controller set disk) requires DC24V power supply, and by the fire alarm controller to provide;
2, when the current use of fire telephone module access, the module itself needs to provide DC24V power supply, power supply by the fire alarm controller output power bus. The fire telephone module, respectively, access to the power bus, telephone bus (fire phone controller output), and output two bus access to the phone jack and telephone extension.
