What is Computer Communications ?

Computer Communications - Describes a process in which one computer transfers data, instructions and information to another computer(s). Some devices that can serve as sending and receiving devices in a communication system are:

(a) personal computers
(b) notebook computers
(c) Web-enabled cellular telephones
(d) Web-enabled handheld computers
(e) WebTV™
(f) GPS receivers

The primary function of a communications device such as a modem is to convert or format signals so they are suitable for the communications channel or a receiving device. When using a telephone line as the communication channel, you need to convert between analog and digital signals.

An analog signal consists of a continuous electrical wave. Computers however, process data as digital signals. A digital signal consists of individual electrical pulses that represent the bits grouped together as bytes.

Circuit Switching vs Packet-Switching

Circuit switching – centrally controlled, single-connection method where all data travels along a single path between sender and receiver. Most local telephone traffic today is still handled using circuit switching technologies.

Packet switching – files and messages are broken down into packets that are labeled electronically with codes for their origin and destination. Packets travel from computer to computer along the network until they reach their destination. Routers are computers that an individual packet encounters on its trip through the network that determine the best way to move the packet forward to its destination. Routing algorithms are programs that routers use to determine the best path for the packet. Packet switching networks are more reliable since they rely on multiple routers instead of central point of control and because each router can send individual packets along the best path.

Channel - Communications path between two devices.

Bandwidth - the amount of data that can travel through a communications circuit in one second. The bandwidth that an ISP can offer depends on the type of connection it has to the Internet and the kind of connection you have to the ISP. The bandwidth for a network connection between two points is always limited to the narrowest bandwidth that exists in any part of the network.

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