using RS232 for serial communication


Thread Starter


I am using RS232 chip when needed to transfare data serially to a PC from a microcontroller...
I'd like to know what is the purpose of using RS232...
The purpose of using RS232 is mostly because it is a standard, which means that when properly used, you can connect any RS232 device to any other RS232 device and they will at least not cause electrical problems. RS232 is a standard for electrical connection, it does not specify mechanical, the connector, or data, the protocol. But it is a standard means to connect two devices.

Other standards are RS422, RS423, RS485, and RS530. These provide other ways to connect devices.
i think the purpose is mainly to have the simplest 1 to 1 communication btw 2 devices in a short distant at 19.2k baud rate. rs232 signals are by voltage level with respect to ground.

i use to start serial communication for programming before establishing ethernet. some PLC need first downloading by serial cable before running ethernet. normally,different PLC has its own wiring diagram for serial cable which user can make.
What type of PLC are you using and what software in your PC? RS232 is just the electrical interface, you will need to know what Protocol or language the mirccontroller is using to get access to the data.

Send us more details about your project, than i'll try to help you more efficiently.

Best regards
O. Mourad
Probably, u mean the max232. The purpose of the max232 is to convert the level signals between the PC and microcontroller (in your case) making sure that the system gets the same level logic transmitted by the other. If the microcontroller transmits high level (+5V), the PC also receives high level (-12V). The voltage conversions are the job of the max232.

Please e-mail me: [email protected]. I'd like to know more about your project.

Ashutosh Chandel

The answer is...

Your main objective is to communicate your PC to Microcontroller, so the RS232 serial comm. is just the medium to do so.

You can also have some parallel comm. if your microcontroller supports the same.

As a brief RS232 is the most simple comm. protocol which needs only three transmission lines i.e. Ground, Transmit and Receive. Also using this protocol you can have distance upto 1200 meters between the two devices, which is not possible in parallel communication. Of course there are some drawbacks i.e. the communication is slower than parallel comm. as the data is sent bitwise.

and at last to communicate with a microcontroller RS232 can be the best solution because of its less hardwiring and easy avaliablity features.

If u wish to have more details please send me a request on my mail Id.

Ashutosh Chandel
Engineer - Plant Automation
[email protected]