SLIP (Serial Line IP), and PPP (Point-to-Point Protocol) are a widely used protocol for sending IP-packets over a serial link. A number of institutions offer dial-up SLIP and PPP access to machines that are on the Internet, thus providing IP-connectivity to private persons (something that's otherwise hardly affordable).
To run SLIP or PPP, no hardware modifications are necessary; you can use any serial port. Since serial port configuration is not specific to TCP/IP networking, a separate chapter has been devoted to this. Please refer to chapter- for more information.