• Interfacing describes a broad group of methods that allow us to pass data between computers and other devices.
• To connect PLCs for communication, we first need connecting wires. This is the followed by a communication protocol.
• There are a few common methods of interfacing,
serial - a single point to point connection allows data communication over a small number of wires (eg. RS-232)
parallel - multiple wires are used for data communication. This is only common for older data bus designs such as printer parallel port and GPIB buses.
network - networks allow multiple connections to pass data. These actually are built upon the basics of serial and parallel communications