Modes Of Network Communication:-
Modes of network communication refer to the methods or the ways information is transmitted from the one place to another.
The follow are the modes of data communication
• Simplex, Half Duplex, And Full Duplex
• Synchronous And Asynchronous
Simplex, Half Duplex, And Full Duplex Communication Modes:-
In the simplex mode, the communication takes place in online one direction.In this mode communication is unidirectional, i.e the communication can only take place in one direction and it is not possible for the receiver to sent data back.
For Example data being sent to electronic notice board in the train stations and airports.
Radio and television broadcasting are also example of simplex transmission .Transmission of the information from a computer to a printer is also in one direction.
Half Duplex Mode:-
In the half duplex mode the communication take place in bot direction but not at the same time.The signal can only be sent or received at one time.A common example of this type of communication is the use of walkie talkies, where each of the person communicating must indicate when they have finished speaking.Half duplex transmission is used also in transaction oriented system, for example communication between a computer and the credit card machine.
Full Duplex Mode:-
In the full duplex mode, the communication take place in bot direction at the same time.In this mode, both sender and receiver can sent and receive the data simultaneously, for example two or more computers are connected to a network device such as a switch that provides full duplex activity.It is the fastest bi-directional mode of the communication.The full duplex mode is like two way street, with traffic flowing in bot direction at the same time.
One common example of full duplex communication is the telephone network.Where two people are communicating by a telephone line, both can talk and listen at the same time.Also full-duplex mode is the most suitable for data communication between computers.
Asynchronous And Synchronous Transmission:-
Asynchronous And Synchronous transmission are the two different methods which are used for transmitting character between components within a computer or from computer to other devices such as printer, modem.
In Asynchronous transmission, the time interval between two characters is variable and not fixed.The computer devices can exchange information at their own rate, show or fast.Start and stop bits are used in Asynchronous transmission.These bits provide timing for the connection between the sender and receiver.The start bit tells the receiver that a character is coming and stop bit indicates that the transmission of the character has ended.This type of transmission is ideal for slow speed communication when gaps may occur during transmission.Example of Asynchronous transmission is keyboard data transmission.
In Synchronous transmission, the time interval between two characters is always the same.In this method two communicating devices are Synchronous and they continue to sent character in order to remain Synchronized, even if there is no data to be transmitted.A special Idle character is sent when there is no data for the transmission.It does not require transmission of start and stop bits.It sends data as one long bit stream or block of data and each bit is sent one after other.The receiver count the bits and reconstructs the sent information in bytes.It is essential that timing is maintained as there are no stop and start bits and no gaps.Accuracy is dependent on the receiver keeping an accurate count of the bits as they come in.
Synchronous transmission is faster that the Asynchronous because fewer bits have to be transmitted: i.e only data bits are no extra control bits are sent.The best example of Synchronous transmission is the data transmission between devices in the network communications links.