15. "Off-talk" communications
A service which uses the ordinary telephone lines when the house phone is not in use to offer music, stock market information, administrative information and local announcements from "off-talk" information centers of the local authorities or the third sector.
16. IC card
A card which performs various functions such as memory, calculations and referencing, by LSI circuit incorporated in a particular part of a traditional magnetic card.
17. Optical card
A plastic card containing an internal memory device which reads and writes by light and has a large memory capacity of up to 2.5 Mb per card.
18. Public lines
Telecommunications lines carrying communications between numerous undesignated users.
19. Private lines
Telecommunications lines carrying communications between specified parties according to a lease contract.
20. ISDN (abbreviation of "Integrated Services Digital Network")
A system which provides various services such as telephone, data and facsimile through a single
telephone number by unifying the information into a digital signal.
21. DDX (abbreviation of "Digital Data Exchange")
A network which transmits vast amounts of data at high speeds, and which offers two types of service: line switching and packet switching.
22. Internet
A global network which connects computer networks to each other and allows users to surf the network through the use of WWW servers and to send and receive electronic mail.
