COMPUTER NETWORK LECTURE ONE

Computer networks
Communication is the process of transmitting the messages that carrying information, where the two computers can be communicated with each other if the two conditions are available:
Translating the data into the signals can be transmitted between the two computers. Providing a communication channel between them for transmitting and receiving the signals through it.The fundamental purpose of a communications system is the exchange of data between two parties. Figure 1.l.b presents one particular example, which is the communication between a workstation and a server over a public telephone network. Another example is the exchange of voice signals between two telephones over the same network. 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 ransforms that bit stream into an analog signal that can be handled by the telephone network.