Data communication is the function of transporting digital signal from one digital device to another. Data transmission and data communications means two different things. Data communications has a much wider meaning which embraces not just electrical transmission but many other factors involved in controlling, checking and handling the movement of information in a communication-based computer system.
Basic Data communication setup
The simplest means to provide a data communication setup is to directly connect two DTEs (Data terminating equipment, usually computers) by a proper interface like RS232c. This is feasible only for short range communication and requires only for short range communication and requires no Modem but requires high quality coaxial cables.
The standard method of setting up data communication between tow DTEs lying far distance apart is to use –
Telephone network or dedicated transmission medium
Such as setup is shown below –
As shown above modems use digital signals from a DTE to modulate a self generated audio frequency signal in voice telephony range so that the digital information can travel across the telephone network and at receiving end demodulation of analog signal takes place to recover the sent digital signals across the line. Now, this is one of the basic and standard data communication method used.