Differences Between RS232 and RS485

RS-232 adopts an unbalanced transmission method, also known as single ended communication. The data signals of the receiver and transmitter are relative to the signal ground. For example, when using the DB25 connector, the data sent from the DTE device is at a level of 2 pins relative to 7 pins (signal ground).

The data signal of RS-485 adopts differential transmission method, also known as balanced transmission, which uses a pair of twisted pair wires, with one wire defined as A and the other wire defined as B.

The main difference between RS-232 and RS-485 as below.

1.The transmission methods are different. RS-232 adopts an unbalanced transmission method, also known as single ended communication RS485 adopts balanced transmission, that is, differential transmission.

2.The transmission distance varies. RS-232 is suitable for communication between local devices, with a transmission distance generally not exceeding 20m. On the other hand, RS-485 has a transmission distance ranging from tens of meters to thousands of kilometers.

3.RS-232 only allows one-to-one communication, while RS-485 interface allows up to 128 transceivers to be connected on the bus.

4.RS-232 is full duplex, allowing it to send and receive data in two directions. RS-485 is half-duplex, so it can only transmit data one way at a time. 

5.Maximum baud rate for transmitting data

The RS232 transmission rate is relatively low, with a maximum baud rate of 19200bps. Although the transmission speed is slow, it is still very practical in many situations.

The maximum data transmission rate of RS485 is 10Mbps. The transmission speed has increased significantly.