| 摘要 |
PURPOSE:To easily cope with the modification of the specification of a key telephone system and to eliminate the ROM large capacity by providing an IC card in which control data (control program) corresponding to a user is registered to a key telephone main system freely attachably and detachablly, and supplying the control data from this IC card. CONSTITUTION:In the IC card ICCD to be mounted on the key telephone main system ME, the control program corresponding to the specification required by the user is stored. At the time of inserting the IC card ICCD to a connector 5 provided to the system ME, the main system ME is supplied with the power, and at the same time, the address bus, the data bus, and the control line of the main system ME and those of the IC card ICCD are connected to each other respectively. The IC card ICCD is a substitute for the readonly memory ROM of a conventional main system ME; the control circuit CPU of the main system ME IS operated by the program stored in the IC card ICCD beforehand, while the control circuit KPU of the key telephone sets KT-1,-, KT-m are operated by the program stored in a readonly memory KOM beforehand.
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