To provide the data communication system where the communication cost of data communication is reduced and to provide the communication equipment and the communication method used for this system.

A PHS data communication device 31 allows an external device to store data sent in an inter-salve-set direct communication mode from PHS data communication devices 121, 123 which are respectively provided to external devices 111, 113 placed dispersedly, detects whether or not the stored data reaches a preset storage reference amount and sends the data having been stored in the external device 32 in a public mode to center devices 51, 52 in a prescribed sequence when the result of detection denotes that the data reach the preset storage reference amount.