A selection device monitors 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 {TAIL ~ broadcast} of {HEAD ~ its message} through the star coupler 
A selection device monitors 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 { TAIL ~ broadcast } of { HEAD ~ its message } through the star coupler
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