What is the height of a household fire alarm controller?
Yes, the 2 power supply is powered by two alternating current, using a two way power converter, one way off the power line, the other can be powered immediately.
Direct current is the storage battery in the main engine. After 24VDC, the DC power of the battery can be supplied to the fire engine for a period of time after the main power has been cut off.
The price is uneven, see what brand, and generally 60-190 on it. You can make it yourself, very simple.
