dial-up
Dial-up Internet access is a form of Internet access that uses the facilities of the public switched telephone network (PSTN) to establish a connection to an Internet service provider (ISP) by dialing a telephone number on a conventional telephone line. The user’s computer or router uses an attached modem to encode and decode link layer frames and control information into and from audio frequency signals, respectively. Software of the computer encapsulates or extracts Internet Protocol packets from the data stream. Despite the proliferation of high-speed Internet access (broadband), dial-up Internet access may be used where other forms are not available, such as in some rural or remote areas.