The RS232 standard is one of the oldest physical communication standards in computer world. The standard defines low-cost serial communication in a robust way where bits are sent sequentially on a copper line. It was originally defined for connecting devices such as computers, terminals and printers to modems. This equipment is connected through their serial port. Nowadays, the computer to computer link with a so-called null modem cable is commonly used.
The original serial port definition limited the maximum transfer speed to 20 kbps, but practice has shown that higher bandwidth is possible. To overcome these limitations, the RS232-E standard allows much higher communication speeds than its predecessor.
These pages provide not only information on the standard itself, but also on how to use serial communication in practice, several connection possibilities to the serial port etc. This includes handshaking and how to choose the right null modem cable for computer to computer communication. 