Some non-standard USB devices use the 5 V power supply without participating in a proper USB network, which negotiates power draw with the host interface. These are usually called USB decorations.[citation needed] Examples include USB-powered keyboard lights, fans, mug coolers and heaters, battery chargers, miniature vacuum cleaners, and even miniature lava lamps. In most cases, these items contain no digital circuitry, and thus are not standard compliant USB devices. This may cause problems with some computers, such as drawing too much current and damaging circuitry. Prior to the Battery Charging Specification, the USB specification required that devices connect in a low-power mode (100 mA maximum) and communicate their current requirements to the host, which then permits the device to switch into high-power mode.
బ్యాటరీ ఛార్జింగ్ స్పెసిఫికేషన్కు ముందు యుఎస్బి స్పెసిఫికేషన్ అవసరం ఏమిటి?
that devices connect in a low-power mode (100 mA maximum) and communicate their current requirements to the host