PURPOSE: To attain the communication of a central station to lots of terminal stations within a prescribed time by raising a carrier having the 2nd frequency when the terminal station receives a transmission signal from the central station, sending the data to the central station, descending the level of the carrier after the end of data transmission so as to send/receive the data between the central station and each terminal station.
CONSTITUTION: A master communication equipment 1-A being a central station sends a data S1 to a slave communication equipment 1-B1 at first as a transmission signal 3A, and after the end of transmission of the data 51, an interblock time T3 is provided to send a data S2 to a slave communication equipment 1-B2 of the next stage by using a transmission signal 3A independently of the reception of a data D1 sent from the slave communication equipment 1-B1. Then the slave communication equipment 1-B1 starts raising the transmission signal 3B1 from the point of time when the data 51 is received and after a time required to raise the transmission signal 3B1 elapses, the data D1 is sent. Then the slave communication equipment 1-B1 starts descending the transmission signal 3B1 from the point of time of the end of transmission of the data D1 and the slave communication equipment 1-B2 raises the transmission signal 3B2 when the data S2 is sent.
IMAI YASUMASA
KURUMA HIDEKI
SONE FUMIKI
WATARI TATSU