Instrument Control Toolbox

The Serial Port Interface Standard

Over the years, several serial port interface standards for connecting computers to peripheral devices have been developed. These standards include RS-232, RS-422, and RS-485 -- all of which are supported by the serial port object. Of these, the most widely used standard is RS-232, which stands for Recommended Standard number 232.

The current version of this standard is designated as TIA/EIA-232C, which is published by the Telecommunications Industry Association. However, the term "RS-232" is still in popular use, and is used in this guide when referring to a serial communication port that follows the TIA/EIA-232 standard. RS-232 defines these serial port characteristics:

• The maximum bit transfer rate and cable length
• The names, electrical characteristics, and functions of signals
• The mechanical connections and pin assignments

Primary communication is accomplished using three pins: the Transmit Data pin, the Receive Data pin, and the Ground pin. Other pins are available for data flow control, but are not required.

Note    In this guide, it is assumed you are using the RS-232 standard. Refer to your device documentation to see which interface standard you can use.

What Is Serial Communication?

Connecting Two Devices with a Serial Cable