4.4 Modes of digital communication

Digital communication!modes

Digital communication systems generally follow the architecture described in Section 4.1; however, there are many variations in the implementation of the architecture for different types of communication system. The reason why there are differences is that different applications and environments call for different specifications. For instance, long-distance transmission over cables is much different than short-range wireless communication. However, if every product with a communication system had its own methods, the wheel would be constantly reinvented, shared channels (e.g., the radio spectrum) would be in disarray, and infrastructure would be unnecessarily duplicated. For these reasons, communication standardsDigital communication!standards have been developed and widely adopted.

Before turning in the next section to look at some standards of particular interest for real-time computing, we review three important modes of digital communication: serial/parallel, synchronous/asynchronous, and simplex/duplex. Standards are usually described, in part, …