Posts

Image
The Communication Model: The fundamental purpose of a communications system is the exchange of data between two parties. The key elements of the model are:- Source: - This device generates the data to be transmitted; examples are telephones and personal computers. Transmitter Usually, the data generated by a source system are not transmitted directly in the form in which they were generated. Rather, a transmitter transforms and encodes the information in such a way as to produce electromagnetic signals that can be transmitted across some sort of transmission system. For example, a modem takes a digital bit stream from an attached device such as a personal computer and transforms that bit stream into an analog signal that can be handled by the telephone network. Transmission System . This can be a single transmission line or a complex network connecting source and destination. Receiver. The receiver accepts the signal from the transmission system and converts it into a ...
Data Communication Data communications are the exchange of data between two devices via some form of transmission medium such as a wire cable. For data communications to occur, the communicating devices must be part of a communication system made up of a combination of hardware (physical equipment) and software (programs). The effectiveness of a data communications system depends on four fundamental characteristics: delivery, accuracy, timeliness, and jitter. I. Delivery . The system must deliver data to the correct destination. Data must be received by the intended device or user and only by that device or user. 2. Accuracy . The system must deliver the data accurately. Data that have been altered in transmission and left uncorrected are unusable. 3. Timeliness . The system must deliver data in a timely manner. Data delivered late are useless. In the case of video and audio, timely delivery means delivering data as they are produced, in the same order that they are produced,...