Abstract: An IC memory device has input/output terminals, a holder for detachably housing the memory device, and an IC card-type adapter which is provided with connection terminals to be connected to the terminals of the memory device housed in the holder. The memory device is solely attached to or detached from a small electronic device such as a wrist watch and makes serial data transmission/reception therebetween. The memory device is set in the adapter and makes parallel data transmission/reception between it and an electronic device having connection terminals to the connectors of the adapter.

Abstract: The invention relates to an integrated circuit memory device 1 in which connecting terminals 11b for transmitting signals between itself and an external device are provided on a bottom surface of a coin-shaped case 10 containing an integrated circuit memory chip 12. A changeover switch 20 for changing the memory chip 12 to a data-writing mode is provided at an outer peripheral side portion of the coin-shaped case 10. The switch 20 has an operation knob 24 located in a notch 13A formed in a ring-shaped core member 13 of the case 10, and a contact plate 22 formed integrally with the knob 24. The switch 20 selectively switches the memory chip 12 in a data-writing mode and in a data-writing protect mode. In the data-writing protect mode, the write (WR) signal supplied to a write terminal of a circuit substrate 11 is prevented from being input to a write electrode of the memory chip 12.