To make correctable time data at a communicating destination by recognizing the time data of its own terminal and another terminal in before data communications and adjusting the time data of one terminal to that of the other when the difference of the time data exceeds an allowable time difference.
Before data communications between a data collecting unit U and a terminal radio unit Ua, in order to secure the reliability of data, timers for timing are incorporated in the CPUs21 and 31 of the respective units U and Ua. Thus, the respective flash memories 22 and 32 of the unit U and the unit Ua are provided for correcting time data to collate time data between both of the units U and Ua. When the difference between the time data of both of the units exceeds an allowable time difference as communication data, the CPU21 of the unit U on a host side sets time data timed by the timer to be a reference time to adjust the time of the timer of the CPU31 of the unit Ua on a slave side.
NISHIMURA ITARU
ONO KENICHI
KUDOME TORU
