Remote data entry is performed in such a manner that a plurality of entry items and a plurality of data items are caused to collectively enter within one communication and the check sum is calculated simultaneously with the data entry so that abnormality of the data is easily detected even if the contents of the entry data are changed due to the abnormality occurring in a facsimile apparatus. Data is collectively stored in a receiving buffer and a great quantity of data is caused to remote enter if the capacity of the buffer permits. After all remote data entries have been completed, the check sums of all entry memory regions are performed so that the memory capacity of the program code of the check sum is saved.