On these pages

RS232 specifications

Serial UART info

I/O ports and IRQ's

Flow control and handshaking

Which RS232 null modem?

RS232 support forum New

Also on this site

RS232 pin assignment

RS232 DB9 to DB25 converter

RS232 loopback test plug

Serial printer cables

RS232 spy / monitor cable

RS232 PLC cables

USB, universal serial bus

Software downloads

Introduction to the RS232 serial port

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.

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