This manual describes two computers configuration, one acting as server and other as client. The server computer will be configured to provide internet services and the client to make use of those internet services provided by the server computer. The connection medium both client and server computer use is the telelphone line (i.e., the same medium you use to realize phone calls). In this configuration, both client and server computers use special devices named Modems to transmit data in form of sound across the telephone line. The configuration described in this chapter could be a good choise when the only communication medium you have access to is a telephone network.