Self-Powered Versus Bus-Powered M Series USB Devices
Bus-powered M Series devices require no external power source. Examples of these devices include the NI 6210, NI 6211, NI 6212, NI 6215, NI 6216, and NI 6218. Self-powered M Series devices, on the other hand, require an external power source such as a wall outlet or a battery. Self-powered devices can drive higher currents than bus-powered devices. Examples of self-powered M Series devices include the NI USB-6251 and NI USB-6259.