Study Material for the Students

Data Communication Terminologies There are several common terminologies used in data communication literature: Channel: The word channel refers to the portion of a link that carries a transmission between a given pair of lines. One link can have many (n) channels. Data Rate: The data rate defines the number data elements (bits) sent in 1 second. The unit is bits per second (bps). Signal Rate: The signal rate is the numbers of signal elements sent in 1 second. The unit is baud . The data rate is sometimes called the bit rate : the signal rate is sometimes called the pulse rate, the modulation rate, or the baud rate. One goal in data communications is to increase the data rate while decreasing the signal rate. Increasing the data rate increases the speed of transmission; deceasing the signal rate decreasing the bandwidth requirement. Bandwidth: Bandwidth can be used in two different contexts with two different measuring values:- Bandwidth in Hertz: Bandwidth in ...

The Inter Space Inter space is a java implementation, which provides a high level common java interface to middleware. It enables re-facing legacy applications using existing development tools like VB. It works like a gateway. Switching Techniques Data communication takes place by two devices that are directly connected by some transmission media. Whenever we have multiple devices, we have the problem of how to connect them to make one-to-one communication possible. Its best solution is switching . A switched network consists of a series of interlinked nodes, called switches. Switches are devices capable of creating temporary connections between two or more devices linked to the switch. Consider the following figure-   Types of switching- Circuit Switching: Circuit Switching is a method in which a dedicated communication path is established between two devices through one or more intermediate switches. The telephone system uses this type of switching...

Networks A network is a set of devices (also known as nodes) connected by communication links. A node can be a computer, printer, or any other device capable of sending and/or receiving data generated by other nodes on the network. Categories of networks There are following categories of the networks 1.       PAN 2.       LAN 3.       MAN 4.       WAN Personal area network A personal area network (PAN) is a computer network used for communication among computer and different information technological devices close to one person. Some examples of devices that are used in a PAN are mobile phones, personal computers, printers, fax machines, telephones, PDAs, scanners, and even video game consoles. A PAN may include wired and wireless devices. The reach of a PAN typically extends to 10 meters. A wired PAN is usually constructed with USB and Firewire connections while ...