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