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.
The first two can be found on your computer (and should be labeled as such), and the third kind applies to âdumbâ wall chargers. In the USB 1.0 and 2.0 specs, a standard downstream port is capable of delivering up to 500mA (0.5A); with USB 3.0, it moves up to 900mA (0.9A).asically, it looks like wall chargers communicate to the device that they ARE a wall charger by shorting the data lines (D-and D+). When the device sees shorted data lines, it knows that it can draw up to 1.5A â thatâs what the Battery Charging Spec dictates.