What is RS232 and What is it Used for?

▶ Check out the full blog post over at

==========================

Today you will learn about RS232. It is a phrase you may hear fairly regularly in industry, especially by the older guys. Hopefully this video will clear some things up for you.

What exactly is RS232? First and foremost, it is a form of serial data transmission. Or simply put, it is a form of communication. Most people simply called it a serial connection.

What exactly is RS-232? First and foremost, it is a form of serial data transmission. Or simply put, it is a form of communication. Most people simply called it a serial connection.

At one time, it was the most used form of data transmission. You will probably recognize the standard 9 pin DB9 cable. Simply put, RS-232 transmits signals using a positive voltage for a binary 0 and a negative voltage for a binary 1. But what do the PLCs use RS232 for?

PLCs use RS232 to talk to other modules or even other PLCs. These modules can be anything that also uses RS232 such as, an operator interface or HMI, computers, motor controllers or drives, a robot, or some kind of vision system.

==========================

Missed our most recent videos? Watch them here:

=============================

To stay up to date with our last videos and more lessons, make sure to subscribe to this YouTube channel:

=============================

=============================

#RealPars #RS232

[MrSloika]

Max cable length of 50 feet was the standard using the cabling that was available when the RC-232 standard was developed back in the 60s. It's better to say that the max cable length is limited to 2500 pF of capacitance. Cable capacitance is determined by the type of cable used. With CAT-6 cable 2500 pF is about 500 ft. In the real world it's possible to reliably run RC-232 over a CAT-6 cable up to 100 feet without any problems.

[renegadeflower]

Thanks for letting us know about it. Now including RS485, I now know what RS232 cable is and its disadvantages.RealPars is the place to learn automation and not just programing PLCs.

[rty]

Omg I ran so many RS-232 cables throughout a building for terminals. Back in the day RS-232 was on a DB25 using full hardware handshake. Also 20ma current loop was used for long hauls. Originally used to replace telegraphy equipment along the railroad. Western union used it for telegrams on Teletype equipment.
Dont be fooled just by DB9 connectors as RS-232 was originally DB-25 (25 pin connectors)

[Gavin_Gonzalez]

This Channel is so good Man, many thanks

[danielhedger]

Learning about this in college. Very helpful! Thank you!

[aliiqrar]

great work RealPars. i just wanna say thank u for the work you guys are doing ❤

[eddieram]

You mentioned DTE and DCE, computer being DTE but what would a vinyl cuter printer be? DTE or DCE? also what is difference between DB9 male pinout 1 and DB9 male pinout 2? last question, i read that between to DTE devices i will need a RS-232 null modem cable, would that be correct? Thank you in advance.

[salemeister]

I’m watching this trying to understand why it takes twice as long to upload software to our A-10’s via rs 232 vs mil std 1553 and this sort of helps it makes sense. So thank you. Also for some reason it behaves differently when you upload it on either standard which is confusing.

[vylbird]

RS232 in the real world is full of nasty surprises though. A lot of equipment isn't entirely compliant.
- The correct voltage levels are +-12V, which is great for driving long cables. But it's also difficult (ie, expensive) to generate electrically from the supplies typically available in equipment, so corners are sometimes cut and the voltage reduced. +-5V is so much easier to make, it's just a cheap charge pump, and most equipment is fine with it over short cables. But then you happen to have that one piece of equipment that isn't, or a long cable, and the connection doesn't work - for reasons you won't be able to identify without electrical test equipment.
- USB-to-RS232 adapters often skip out lines like flow control, RI and DCD. Again, to save money, because most equipment doesn't need these lines. So who will notice? Until someone does. So you end up with adapters that seem to work, pass any test, work on most equipment - but then you start on certain devices, and they fail. Worse, those flow control lines only get used under substantial data transfer - so the link may appear to pass every test, you may even be able to use it to configure your device without any problems, giving the impression that all is well and your serial link is fine - then you send a page full of text to print or a long string of g-code commands and they end up corrupted.
- There's no autoconfiguration. You need to get every setting right - bit rate, parity, start and stop bits, byte length, flow control method. A misconfiguration of length or flow control again may appear to work when testing, but then fail when sending the intended data through.


With RS232, you really need to know everything there is about how it works in order to recognise and diagnose problems. There's a reason USB replaced it, and it's not just because USB is faster.

[bahmannosratollah]

Thank you so much for your everyday information.

[Xsahar_tavafiX]

Thank you for making this videos. I enjoyed every videos I watched in your channel.

[srivatsaa.r.]

SIR
Yr video "RS232"

Wached yr above video and I LIKED IT. I find it is useful to know.
Positive features of yr video are:--
1 Excellent video production (technically) and presentation.
2. You spoke in OXFORD ENGLISH, distinct / clear pronounciation and clearly audible.
3. Precise compact information presented to make the viewer understand clearly.
4. Lastly yr summarising what all you explained earlier/ all the while helps memorising key important points.
Vatsa INDIA.

[SJ-hwbx]

Subscribed...absolutely perfect, straight out information with out all the garbage ya get with 99+% of you tube videos!!

[ashikazarudeen]

In my college days I was study lot about that but I could completely understand after your video..

[DeedarTVMax]

Thanks to all the channels who helped me to to understand RS 232 and rs485

[vishveshpatel]

Best video.
What i like is easy language

[kfl]

Great video. I have an avr and a tv with rs232 on them and was not sure how or why they would be used. I think in those two instances they are used to upgrade the firmware.

[lct]

Hi realpars
When connecting 3 or more devices together do you use a cable splitter? Will it work if i cut the cable and connect the colors together to make a daisy chain?

[davidabba]

well explained thank you! and i also had a laugh with the slow RS232 :)

[aarshavarsenal]

Super... Every video is just awesome. Keep doing