What are the three ways of data communication?

Parallel communication vs. serial communication.

In data communication, according to the number of data bits transmitted each time, the communication mode can be divided into: parallel communication and serial communication.

Parallel communication is the simultaneous transmission of 8-bit binary data at a time, requiring 8 transmission lines from the sender to the receiver. The parallel mode is mainly used for short-range communication, such as data communication inside a computer is usually carried out in parallel mode. The advantage of this method is that the transfer speed is fast and the processing is simple.

Serial communication transmits only one bit of binary data at a time, and only one transmission line is required from the sender to the receiver. Although the transmission rate of the serial mode is low, it is suitable for long-distance transmission, and the serial communication mode is generally used in the network (such as public systems).

Simplex, half-duplex and full-duplex communication.

Simplex communication only supports data transmission in one direction, also known as one-way communication. For example, radio broadcasting and television broadcasting are simplex communications.

Half-duplex communication allows data to be transmitted in both directions, but at the same moment, data is only allowed to be transmitted in one direction, and it is actually a simplex communication that can switch directions. That is, both parties can send the message, but not both at the same time, (of course, they cannot receive it at the same time). This method is generally used in the non-backbone lines of computer networks.

Full-duplex communication allows data to be transmitted in both directions at the same time, also known as bidirectional simultaneous communication, that is, both sides of the communication can send and receive data at the same time. For example, modern ** communication provides full-duplex transmission. This type of communication is mainly used for computer-to-computer communication.

Simplex, half-duplex, full-duplex.

Synchronous copy mainly includes bit synchronization and character bai synchronization.

Bit synchronization: The purpose is to enable the receiver to correctly accept each binary DAO bit. Generally, there are two methods: self-synchronization and external synchronization.

The self-synchronization method refers to the receiver directly using the characteristics of communication coding to obtain synchronization information from the data block, including using a unique signal to activate the receiving action, or using the level transformation in the data block to adjust the receiving sampling pulse.

The external synchronization method means that the sender sends a series of synchronous clock sequences to the receiver before sending the data, and the receiver locks the received frequency according to the clock pulse frequency and timing, so that it is always in sync with the sender during the process of receiving the data.

Character synchronization, also known as group synchronization, is designed to allow the receiver to strive to identify the data (often a single character) in order to form the complete information. Obviously, character synchronization is based on bit synchronization, and only when a unique synchronization pattern is recognized, can it be true data reception.

**Target..