On receipt of a request related to picture display from a user terminal, a central device transmits an instruction to {HEAD ~ the plurality} of {TAIL ~ 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 
of
On receipt of a request related to picture display from a user terminal , a central device transmits an instruction to { HEAD ~ the plurality } of { TAIL ~ 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD 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