Direct links - You can create a direct link to another computer by running RS-232 cables between serial ports on the two machines. Direct links are useful where two computers communicate regularly and are physically close--within 50 feet of each other. You can use a limited distance-modem to increase this distance somewhat.
Telephone lines - Using an automatic call unit (ACU), such as a high-speed modem, your machine can communicate with other computers over standard phone lines. The modem dials the telephone number requested by UUCP. The recipient machine must have a modem capable of answering incoming calls.
Network - UUCP can also communicate over a network running TCP/IP or other protocol family. After your computer has been established as a host on a network, it can contact any other host connected to the network.
This chapter assumes that your UUCP hardware has already been assembled and configured. If you need to set up a modem, refer to System Administration Guide and the manuals that came with the modem for assistance.