Fire alarm systems need to be inspected, tested and tagged annually. Testing must include all smoke detectors, manual pull devices, annunciators, visual indicators and strobes, control units, voice/alarm communications systems and any other devices that are a part of the fire alarm system.
it will need a port like this one to get more power from the usb since it only give 5.0 volts and this powered usb give up12 to 24 volts so you dont have that in a laptop and there is no way it could raise the power on the usb port in a laptop without damaging something .http://en.wikipedia.org/wiki/Powered_USB.
Each USB port can provide power to connected devices. This is not always necessary, especially if the connected devices have their own external power supply. But some devices need the power provided by the USB port to function or reload batteries. A problem with this is that USB ports can only supply a maximum of 500 mA (that's milliampere) which is usually not a problem if one device is connected to the port.