초록 ▼

According to a portable medium (IC card) of this invention, a memory area is divided into a system program area and a user program area. A text transmitted between the IC card and a host system connected thereto includes a command text and a response text. The command or response text includes a fla

According to a portable medium (IC card) of this invention, a memory area is divided into a system program area and a user program area. A text transmitted between the IC card and a host system connected thereto includes a command text and a response text. The command or response text includes a flag indicating that the text is written in the user program area or the system program area. The memory area has a conversion table for a function code and the start address of a program corresponding to the function code. The conversion table is looked up using the given function code as a parameter, thereby obtaining the start address of the corresponding program. The memory area has a correspondence table between a newly added function code and the start address of an added function program. The added function program is selectively executed.

대표청구항 ▼

A portable electronic device detachably connected to an external host system, comprising: memory means for storing a system program and a user program; command text generating means for generating a command text containing data indicating whether a text transmitted to the portable electronic device

A portable electronic device detachably connected to an external host system, comprising: memory means for storing a system program and a user program; command text generating means for generating a command text containing data indicating whether a text transmitted to the portable electronic device from said external host system is used to write the system program or the user program into said memory means, said command text having a start code field, a text length field, a command field, and a check code, said command field containing a specified bit which indicates whether the text transmitted to the portable electronic device from said external host system is used to write the system program or the user program into said memory means; and response text generating means for generating a response text containing data indicating whether a text transmitted from the portable electronic device to the host system is used to write the system program or the user program into said memory means.