{HEAD ~ the second device} is driven by {TAIL ~ the second power supply}, and capable of performing a communication via the bus in the condition in which the pull up voltage is equal to the second predetermined voltage, wherein 
is driven by
{ HEAD ~ the second device } is driven by { TAIL ~ the second power supply } , and capable of performing a communication via the bus in the condition in which the pull up voltage is equal to the second predetermined voltage , wherein
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH