{HEAD ~ A selection device} monitors {TAIL ~ all} of the incoming channels, registers and queues all new transmissions on the channels, and, when the star coupler is free, selects one incoming channel for broadcast of its message through the star coupler 
monitors
{ HEAD ~ A selection device } monitors { TAIL ~ all } of the incoming channels , registers and queues all new transmissions on the channels , and , when the star coupler is free , selects one incoming channel for broadcast of its message through the star coupler
HEAD HEAD HEAD HEAD HEAD HEAD HEAD 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH