COMMUNICATION PROTOCOL RS-232

COMMUNICATION PROTOCOL RS-232

Abstract

In the present automated world, the vigorous usage of computers and other micrprocessors; it is important to understand the means of communication between the controller and the controlled variables in the processes in industries or the transfer of data between terminals in any other. If the available resources are to be utilised in the best possible manner; then the specifics of the resource must be known. In the present paper the RS-232 (now better known as the EIA232 standard) one of the oldest serial communication channels, with details of its pin configurations and reference levels for grounding and operational voltage range and its uses are discussed. The RS-232 has 25 pins of which 22 pins are used for the signals and grounding when the end terminals are both different (male at the data termination equipment and female at the data communication equipment), however when the data communication equipment and the data termination equipment have the same terminals (either both male or both female) then the number of pins can be reduced to 9 pins. Sometimes it is required that the 9 pin connecter be interfaced with the 25 pin. This paper gives the cable wiring examples for such interfaces. This paper forms the genisis for  some of the present and future protocols.