This manual describes the configuration of two computers, one acting as server and other as client. The server computer (see ) will be configured to provide internet services and the client computer (see ) to make use of those internet services. The connection medium used by both client and server computer is the telelphone line (i.e., the same medium you use to realize telephone 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 (see ). This infrastructure is made available to you free of charge, however, you should know that maintaining it might cost you both money and time. For example, for each hour the server computer is on production there is an electrical consume that need to be paid every month. Likewise, each call that you establish from the client computer to the server computer will cost you money, based on the location you made the call from and the time you spend connected. To use this infrastructure, people connecting from the client computers to the server computer must agree the conditions described in . It is worth to mention that, you can configure one computer to act both as server and client. In this case, your computer acts as client of another server computer, not the one you have configured in the same computer of your client (i.e., you cannot call yourself and expect to answer any incoming call using the same line you used to make the outgoing call, it doesn't make any sense). Likewise, your server will act as server for another client computer, not the one you have configured. In resume, you can both receive incoming calls or realize outgoing calls using the same telephone line, but only when the telephone line is free from any incoming or outgoing call. This infrastructure could result very useful to you when you want to share IP packages with your friends and the only communication medium you and your friends have access to is a telephone network.