RS232 and RS485, What are the differences between them?

Difference between RS232 and RS485

RS232 and RS485 both are the standard protocols of serial communication used to send and receive data. It is developed by the EIA (Electronic Industries Association) / TIA (Telecommunication Industries Association).

The main purpose of a serial interface is to provide a single path for data transmission wirelessly over a cable. A serial interface is a very good option for communications over any distance greater than several feet.


There are certain points at which RS232 differs from RS485, such as

  • Communication Distance
  • Immunity against electrical noise and ground
  • Numbers of devices
  • Data transmission speed


Specifications of RS232 and RS485:

Specifications RS232 RS485
Voltage System Voltage-Level based Differential
Total Driver and Receiver in one line 1 Driver, 1 Receiver 32 Drivers, 32 Receivers (Only one driver active at a time)
Line Configuration Single-ended Differential
Mode of Operation Simplex of Full Duplex Simplex of Half Duplex
Maximum Cable Length 15 Mt or 50 Feet 1200 Mt or 3000 Feet
Maximum Data Transmission Rate 1 Mbits/s 10 Mbits/s
Typical Voltage Level ±5V to ±15V ±1.5V to ±6V
Receiver Input Resistance 3 to 7 kΩ 12 kΩ
Receiver Sensitivity ±3V ±200mV


Communication Distance

We can communicate a sender and a receiver over a maximum distance of 15 meters in RS232. However, cable length can be extended but with a slower data communication speed.

For RS485, the communication distance between sender and receiver is remarkably longer up to 1200 meters. That is far better than the RS232 and the could be the main reason to pick RS485 over RS232.


Immunity against Electrical Noise and Ground

RS232 operates on a single-ended line technique that performs well while using with a minimal ground potential. However, in electrically noisy environments with different potential levels, RS232 is too fragile and allows data corruption.

RS485 offers higher noise immunity as it operates on a differential-voltage system, which allows it a longer data transfer distance. Lower voltage use of RS485 offers a higher data speed.


Numbers of Devices 

RS232 has only two devices in a network, one is a sender and the other is a receiver.

RS485 is designed for a multi-point system and it can connect up to 32 devices to a single transmitter.


Data Transmission Speed

RS232 can transmit data with a speed of 1 Mbit/s over a distance of 15 meters. While RS485 has a data transmission speed of up to 10 Mbit/s up to a distance of 15 Meter. Although it can transmit data up to 1200 Meter with a speed of 100 Kbit/s.


DB-9 PinOut Diagram

rs232 and rs485



  • Programmable Logic Controllers (PLC)
  • Computer Numerically Controlled (CNC) Machine Tools
  • Robotics Applications
  • Embedded Control Computers
  • Medical Instruments
  • Power Measuring Instruments
  • Printers and Scanners



RS232 has an advantage when short-distance and low-speed are required. It is a simple and low-cost interface. When you want a simple communication interface between two devices only, Two pins full-duplex communication can be easily established using RS232.

RS485 provides a higher speed over a longer distance, so it is used generally in a network with multiple devices up to 32 devices in a single network over a longer distance.

If you like this article then give us your thoughts in the comment section below.


Next Must-Read Articles


You can read more articles about Electrical and you can also find books that boost your knowledge in the field of Instrumentation

Thanks for reading!

Share this blog,

Leave a Comment