Citizen Watch Company, Ltd.

Yuichi Kato

Yoshikazu Koganei

Asao Saito

Shizuo Yamaguchi

Asao Saitoh

A portable information terminal has at least a programming ROM, a work RAM, a data storage memory, an input key, a liquid crystal display panel, a liquid crystal driving control circuit, a built-in battery, and a central processing unit which is operated by using the programming ROM and the work RAM and displays data in the data storage memory on the liquid crystal display panel. Further, the portable information terminal comprises a switching control circuit which outputs a switching signal in accordance with an input signal from an external computer apparatus connected to the terminal, a control signal switching circuit which switches an address bus, a data bus and memory control signal lines which are connected to the central processing unit to an address bus, a data bus and memory control signal lines which are connected to the external computer apparatus in accordance with the switching signal in order to access the data storage memory from the external computer apparatus, and a serial signal switching circuit which switches a PCMCIA bus control signal to a serial signal in accordance with an input signal from a serial interface device which is connected between the portable information terminal and the external computer apparatus. Still further, the portable information terminal comprises a recognition circuit which recognizes the serial interface device and a PCMCIA standard female connector which is connected to the serial connector which is connected to the serial interface device.

Portable information terminal

A card body,has two battery holding sections (,) inside, and two battery holders (,) each containing a battery are housed therein. The two housed battery holders (,) engage locking portions (,) of a stopper (,), thereby setting them unremovable. When the stopper (,) is slid toward one battery holding section (,), the battery holder (,) therein is still kept unremovable, while the other battery holder (,) can be made removable. Thus, even during battery change, at least one battery always remains in the card body to keep supplying a backup voltage to a volatile memory.

Portable information device

LC card

IC card

Growing community of inventors

Tokorozawa, Japan

Yuichi Kato