What Is RS-232 Communication?
Each product that use RS-232 programming has a serial port connector on the rear panel. A microprocessor chip inside checks the command, executes it, and sends the response. When controlling Extron’s products from a central host, such as a touch panel system, you will need the command codes. These are provided in the user’s manual that ships with the device. Each Extron device that uses RS-232 programming also ships with control software for use with Windows® operating systems. The device user’s manual covers programming on two levels: one provides information on installing and using the control software for Windows®, and the other lists and describes commands for writing user programs.
RS stands for “recommended standard”, and 232 is a number assigned to this standard by the Electronics Industry Association (EIA). In fact, the updated name is EIA-232D, but most people still call it RS-232. The standard defines such things as the type of signal used, timing, the number of bits in a character, which bit goes first, how to separate one character from another, and codes to mark the beginning and the end of the message. Because of these standards, serial communication such as RS-232 can be used over ordinary telephone lines. Serial communication means that the bits of information are sent from one device to another, along a single wire. A second wire is used for data traveling in the opposite direction. A third wire is shared as a common ground. Transmitting, or Tx, is the act of sending data from either end, and receiving data is Rx. The Tx and Rx lines cross, so that Tx from one device becomes Rx in the receiving end, and Rx becomes Tx – much like the two ends of a tele
