On receipt of {HEAD ~ a request} related to {TAIL ~ picture display} from a user terminal, a central device transmits an instruction to the plurality of distribution devices and to the plurality of receiving devices, according to a usage condition of the transmission line and the number of simultaneously distributed pictures 
related to
On receipt of { HEAD ~ a request } related to { TAIL ~ picture display } from a user terminal , a central device transmits an instruction to the plurality of distribution devices and to the plurality of receiving devices , according to a usage condition of the transmission line and the number of simultaneously distributed pictures
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH