{HEAD ~ a control unit} that carries out {TAIL ~ connection} and disconnection to and from each of the host computers as sources of print requests according to the host information registered in said registration unit 
carries out
{ HEAD ~ a control unit } that carries out { TAIL ~ connection } and disconnection to and from each of the host computers as sources of print requests according to the host information registered in said registration unit
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL 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