allows for only 125 devices out of I²C's 1024
* supports only the 100 kbit/s "standard mode" and 10 kbit/s "low-speed mode"

The idea was to define a single standard that could be used both inside and outside a computer. A single I²C/A.b controller chip would be used inside the machine, connected on the motherboard to internal devices like the clock and battery power monitor. An A.b connector on the outside would then allow additional devices to be plugged into the bus. This way all