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Author Topic: UART and RS232 - how to use with Arduino  (Read 2888 times)
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I can easily use Arduino UNO's pin3( TXD) and pin 4( RXD) to be able communicate with another device using UART on that device.
Is it possible to use Arduino Uno so that it can communicate with the device using RS232?
Or must I use voltage level convertor?
Thanks

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I can easily use Arduino UNO's pin3( TXD) and pin 4( RXD) to be able communicate with another device using UART on that device.
Is it possible to use Arduino Uno so that it can communicate with the device using RS232?
Or must I use voltage level convertor?
Thanks



If what you are trying to interface with indeed uses true RS-232 using bipolar signal voltages, then you will need a TTL to RS232 converter circuit or module. This not only converts the voltage levels correctly but also inverts the logic signals which is also required.

Keep in mind that I have seen devices claiming to have a RS-232 interface but when looking deep into there instruction manual and or datasheet, they are actually using TTL level serial data link. So study carefully what you have and what it actually requires to be able to wire to the arduino serial data pins.

Lefty
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Thanks for the reply.
I do not need the full ( true)  RS232 protocol .Only convert  voltage level so that I can connect to a device that has UART available.
Or is Arduino 5V ( that  RS232 has) tolerant?
Thank

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Thanks for the reply.
I do not need the full ( true)  RS232 protocol .Only convert  voltage level so that I can connect to a device that has UART available.
Or is Arduino 5V ( that  RS232 has) tolerant?
Thank



I'm sorry I don't fully understand your question and the subject is all about actual details and facts Vs simply the normal standards and practices. Perhaps if you could provide a link to the external device it will provide enough details to confirm what you will actually require?

Lefty
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Quote
Or is Arduino 5V ( that  RS232 has) tolerant?
I also don't quite understand but in no way is the Arduino tolerant of RS-232 voltage levels.

There are a few ways to do this but the the best way I reckon is to use the chips designed for the job, ie MAX232 or equivalents.

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I do not need the full ( true)  RS232 protocol .Only convert  voltage level
As Lefty said, give is a link to the device, we can probably sort it out for you.

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Rob
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Rob Gray aka the GRAYnomad www.robgray.com

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