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.
That way, you will only have to plug one USB cable into your laptop to make everything work. For example, you could buy a Plugable UD-3900 USB 3.0 SuperSpeed Universal Docking Station (Â£99.95), and use two external monitors via its two video ports: HDMI and DVI/VGA. Your laptop would provide the third screen.