Difference Between RS232 and RS485 : Advantages and Disadvantages

The RS232 (Recommended Standard 232) and RS2485 (Recommended Standard 485) are simple forms of serial communication protocols used to transmit and receive data. The data can be transmitted via serial or parallel, the main advantage of parallel communication is that the data can be transferred very fast and the disadvantages are cost per bit will be high and also the crosstalk between the wires will represent that there may be a greater chance of data corruption when transferring long distances. So, in the Oder to overcome all the disadvantages of parallel communication, serial communication has been implemented. This article discusses the difference between RS232 and RS485 serial communication protocols. 

What are RS232 and RS485?

The RS232 and RS485 are the recommended standard protocols used to exchange the data between nodes. The recommended standard 232 is widely used for computer serial interface peripheral connections and it is established by EIA (Electronic Industries Alliance). The recommended standard 485 is also called as EIA-485 or TIA-485 serial communication method. 


Difference between RS232 and RS485

The difference between RS232 and RS485 mainly includes the basics of RS232 & RS484, and its main differences are listed in the tabular form.

Basics of RS232

It is used for data storage, mouse, printers, modems, and many other peripheral devices. It transmits signals from positive and negative voltages for binary 0 and binary 1. The standard form of DTE is Data Terminal Equipment, a common example of this is a computer. The standard form of DCE is Data Communication Equipment, a common example of this is a modem. One common example that many people probably know that is a computer connected to a printer, the RS232 is widely used for printers in working places.

The RS232 protocol allows the system or computer to give commands to the printer via a voltage signal, then the printer receives the commands and completes the print. Some of the disadvantages of RS232 are the speed of the data can be transferred around 20 kilobytes per second, and the maximum length of cable is about 50 feet. 

Basics of RS485

The RS485 is also a form of serial communication faster than RS232. The specifications and configurations of RS485 make faster and extend the data transmission range. Its maximum cable length is 1200 meters that are about 4000 feet. It doesn’t have a standard connector, so many times the old DB-9 connector is used. In place of a connector, terminal strips were used in some applications. It is versatile and faster than RS232, and the greatest feature of this standard is that you can connect up to 32 devices on one system. 

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Main Difference Between RS232 and RS485

The difference between RS232 and RS485 is shown in the below table 

S.NO 

RS232 

RS485 

1 

The line configuration of RS232 is single-ended The line configuration of RS485 is differential  

2 

The RS232 mode of operation is simplex or full-duplex The RS485 mode of operation is simplex or half-duplex 

3 

The maximum cable length of RS232 is 50 feet The maximum cable length of RS485 is 4000 feet 

4 

The maximum data rate of RS232 is 20K bits/sec The maximum data rate of RS485 is 10M bits/sec 

5 

The typical logic levels of RS232 is ±5V to 15 V The typical logic levels of RS485 is ±1.5V to ±6V 

6 

The maximum receiver input impedance of RS232 is 3 to 7K ohms The maximum receiver input impedance of RS485 is 12K ohms 

7 

The receiver sensitivity of RS232 is ±3V The receiver sensitivity of RS485 is ±200mv 

8 

The maximum number of drivers in RS232 is 1 The maximum number of drivers in RS485 is 32 

9 

The maximum number of nodes in RS232 is 1 The maximum number of nodes in RS232 is 32 

11 

It is a point to point connection network It is a multipoint connection network 

12 

It consists of one transmitter and one receiver It consists of 32 transmitters and 32 receivers 

13 

The signaling is unbalanced in RS232 The signaling is balanced in RS485 

14 

The direction of RS232 is uni-direction The direction of RS485 is bi-directional 

 Advantages of RS232 

The advantages of RS232 are 

  • It is widely used for point to point connection between DCE and DTE devices
  • Low cost
  • Due to its simplicity, the interface RS232 is supported in many devices
  • It is free from noise 

Disadvantages of RS232 

The disadvantages of RS232 are 

  • Bandwidth is low
  • Cable length is limited
  • Power consumption increases 

Advantages of RS485

The advantages of RS2485 are 

  • Communication is faster
  • The signal level interface is low
  • Data transmission speed is maximum
  • Good noise immunity
  • Due to the balanced transmission line, it supports multiple slaves and a single master 

Disadvantages of RS485 

The advantages of RS485 are 

  • Only one node can transmit data at a time
  • Special communication cable is needed 

In this article, the difference between RS232 and RS485, advantages and disadvantages of RS232, advantages, and disadvantages of RS485, basics of RS232, basics of RS485 are discussed. Here is a question for you, what are the features of RS232 and RS485?

 

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