Two types of transmission medium are used for communication one is serial and other one is parallel. The main difference between RS232 VS RS485 .they are the way bits are been transferred, Serial interface streams their data, one single bit at a time where as parallel interfaces transfer multiple bits at a time.
Serial interface uses I2C, Ethernet and USB, RS-232, RS-422, RS-485 and many more whereas parallel interface uses IEEE-488 and etc.
Among all the serial communication methods RS-232 and RS-485 are the oldest and widely used nowadays.
Both are widely used in many applications in automation industry for data transmission between two or more devices
RS232 VS RS485:
- RS232 was first introduced in 1960 by the Electronic Industries Association (EIA) as a Recommended Standard.
- It formally defines signals connecting between a DTE (computer terminal), and a DCE (modem).
- They are mostly used in computer serial ports and is best suited for short distance and low speed requirements.
- The maximum cable length allowed in RS-232 is 50 feet. RS-232 uses simplex or full duplex mode of operation.
- It allows one transmitter and one receiver device to communicate on a single line.
- As RS-232 is single ended, means they have common ground for transmit and receive line they are more susceptible to noise compared to RS 485.
- It uses typical logic level ±5 V to ±15 V. It normally uses a nine-pin connector called the DE-9.
RS232 VS RS485:
- It is an extended version of RS232 and used normally for long-distance communication medium.
- RS485, also known as TIA-485(-A) or EIA-485.RS-485 is suitable for higher speed over long ranges.
- The cable length can be 4000 feet. RS-485 uses simplex or half duplex mode of operation.
- It allows 32 devices to communicate on same line that is it supports 32 slave devices.
- It uses typical logic level ±1.5 V to ±6 V. The standard does not define specific connectors.
- Various connection methods have been used, including the RS-232 DE-9 connector. Simple screw terminal connections are common in some types of industrial control equipment.
Difference between RS232 and RS485 Table :
|Communication Mode||Full duplex||Half duplex|
|Data Rate &|
|19.2 kbps at 50 Feet||10 Mbps at 60 Feet|
|+5 to +15v & -5 to -15v||+1.5 to +6v &
-1.5 to -6v
|Currrent Capabillity||500 mA||250 mA|
|Number of Devices||1 Transmiter and 1 Receiver||32 Transmitters and 32 Receivers|
Final Words :
- RS-232 is best suited for short distance and low speed requirements whereas RS-485 are used for long distance and high speed requirements.
- RS 232 are cheaper compared to RS- 485.
- RS-232 is used as a single drop whereas RS-485 is used for multidrop networks.
- RS -232 uses simplex or full duplex mode of operation whereas RS-485 uses simplex or half mode of operation.
- RS-485 are widely used in industries nowadays compared to RS-232.