| 摘要 |
PURPOSE:To detect the destruction of telephone numbers and to prevent mis- transmission and mis-correction, by adding a check code to the telephone number stored in a volatile-memory backed up with a battery. CONSTITUTION:A CPU11 performs various operation processings by using an RAM6 according the programs in an ROM8. In registrating telephone numbers, a registration collating operation memory 7 forms check codes to telephone number information to be registrated and the CPU11 stores the telephone numbers and the check codes in a specified area of a volatile memory 5 backed up with a battery 10. In making a call, this telephone number is given to a dialing tranmission circuit 2 and transmitted to a line terminal 1 as a dial signal, and the memory 7 checks whether or not the telephone number read out from the memory 5 is correct in advance of the said operation. If an error is detected, an alarm circuit 9 gives an alarm and the transitting operation is stopped. |
