Data transmission mode
The mode of data movement depends on the direction of data movement. Data transmission modes are generally divided into three categories; namely-
(i) Simplex mode or unidirectional mode,
(ii) Half-duplex mode or meaning duplex mode,
(iii) Full-duplex mode or pre-duplex mode or duplex mode.
Simplex: The data transmission mode in which data is transmitted only in one direction is called simplex transmission mode. In this method data can be transmitted only in one direction. That is, the sending computer can send data to the receiving computer. But the receiving computer can never send the data to the sending computer. The first computer can only send data to the second computer. But the second computer cannot send data to the first computer.
Half Duplex Mode: At this speed data can be sent in both directions but not simultaneously. When the sending computer sends data to the receiving computer, the receiving computer only receives the data. But the sender cannot send the data to the computer. Data can be sent from one computer to the second computer or from the second computer to the first computer. But cannot be sent together. Example – Walkie talkie system.
Full-duplex mode : In this method, data can be sent simultaneously in both directions. That is, both the sending and receiving computer can understand the start and end of the signal bit. The method for synchronizing different bits while sending a signal is called bit synchronization.
Data transmission speed:
The rate at which data is transferred from one computer to another or from one place to another is called data transmission speed. Data transmission speed is also called Bandwidth. Bandwidth is usually measured in Bits per Second (bps). That is, the amount of bits transmitted per second is called bps or Bandwidth. Based on data transmission speed, data communication speed can be divided into three categories, namely-
(i) Narrow Band,
(ii) Voice Band,
(iii) Broadband.
Narrow Band: The speed of data movement of narrow band ranges from 45 to 300 Bit per Second (bps). Narrow band is used for slow data data communication.
Voice Band : The speed of data movement of voice band is up to 9600 bps. It is commonly used more in television lines. However, in computer data communication, the voice band is used to transfer data from the computer to the printer.
Broadband: The data movement speed of this band is very high from at least 1 Mbps. Broadband is generally used in fiber optic cable, DSL (Digital Satellite Link), radio link. Currently, this band is used for data transfer in computer networking processes.
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