| 摘要 |
PROBLEM TO BE SOLVED: To securely inform maintenance personal of the updated history of circuit boards of each exchange by storing updated history adaptable to updated contents applied to the circuit boards as adaptation information and read the stored adaptation information. SOLUTION: A memory 11 is provided on a circuit board 1 as a means for storing updated history which stores past changes applied to the circuit board 1 as updated history. The updated history of the memory 11 is read and written by a CPU 12 which is a processing unit of the circuit board 1. A maintenance terminal 2 is connected via an I/O port 13 provided on the circuit board 1, and the maintenance terminal 2 is connected with a control computer 4 through a communication line 15. The control computer 4 has a memory (a means for storing adaptation information) 41 which stores adaptation information that the updated history is adaptable or not the updated contents, and a CPU 42 of the control computer 4 reads the adaptation information. |
