What is RS232 and What is it Used for? 

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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.

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

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.

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)

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

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

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

Your channel is ammmazing man

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.

I enjoyed with every video from this channel

Best video. What i like is easy language

thank you for making this video easy to hear to novices like me

Really clear and understood, thanks so much

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.

Keep going :)

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

This video really helped me out. Thanks so much and make more great videos. (P.S. i subbed and hit the bell like you asked)

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

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.

Thank you! very helpful :)

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

Spot on description!

Very clear and useful. Thank you.

This is a great video.

Thank you so much for your everyday information.

Beautiful voice, easy language , great video and very helpful i subscribe in your channel thanks a lot

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

Great show please whats the app u use to create these videos with this form ?

thank you it was quite useful.

Is it possible to connect two or more devices in a parallel connection to a single UART channel for both Rx and TX

I will tell this to the students tomorrow) thanks so much

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

Thanks a lot for this explanation, but i think that the RS232 is a point to point network, wich you can connect only 2 devices, that's why the RS422 and RS485 came after that and allows the multipoint connection, is that correct ? and it's the physical support used also in the Serial Modbus and ProfiBus network.

Thanks!

Thanks. Could you make a video on how to read electronic and electrical diagrams step by step with examples!

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?

Which software you are using ,for make this type of video,please suggest.

Thank you for share..

Can you please tell me what is the difference between usb to RS-232 converter and Modbus protocol

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.

Very good explanation

thank you very much

Thank you so much!

helpful .. thanX

Great channel, great videos, thanks for the efforts, keep it up . Thanks a lot

I have a question, i have an oscilloscope which uses RS232 for PC communication, but it uses a Ethernet-like cable. How do I connect it to my PC? Edit: a RJ45 connector

Keep rocking

thank you

Thank you

What is the bandwidth of serial cable and why it is not being used in real time scenario now a days between router ?

Hi, awesome video , I need some help though. Can you convert a rs232 to ethernet and the back to rs232 with a adaptor? And would the a PLC still be able to understand the data and continue to send and receive data? Thanks

DB9 Two rows of pins, HD15 (VGA) is three rows of pins, they look alike so much.

useful video

Good explanation ....thxx

like always ، good job

Good explanation

thanks ♥

good job you are the best

I have a question that came up to me when watching this video. In minute 4:40, you show something that seems like a "rs 232 Network", but is this possible? Given that rs232 is a point-to-point serial communication, is it possible to connect to the PC and the VFD if the plc above had only one rs232 communication port? there wouldn't have to be a HUB with several rs232 ports or a switch that regulated the information traffic at the points where the connections crossed? Also, since the computer, plc and VFD are DTEs, wouldn't there have to be DCEs for the two points to communicate? Does the network you've designed possibly need more components but for simplication purposes there are omitions? In my opinion, there has to be a HUB between the PC and the VFD that "splits" the cable going to the PLC, considering that both the VFD and the PC already have DCEs that allow communication between different devices. Thank you for your videos; Compliments from Portugal

Great 👍

Very nice video

Very helpful

Trying to figure out an 80's router machine and how it get's programs from a modern server.

This is good teach

In the AV Control Systems Industry RS232 is nearly indispensable.

Problem with our 90's machine. No files available. Moxa boxes for ethernet file transfer. Trying to figure it out..

Thank you sir

Thanks for your great chanal

Can we send video data with RS232? or only control signals

very nice video

nice basic info...

Merci 🙏🏽🙏🏽🙏🏽🙏🏽🔥🇭🇹

Nice information hartly tq

I like you guys

thank you very

thanks

bro explain lvdt and magnetostrictive sensors

Yeah. this is big brain time

AMAZING

Nice

my professor provided us this video and said there will be questions regarding the video in the exam :)

Wonderfull

sir is there any full form of rs in rs 232???

Serial communication can talk with one device only. Am I right?

Can we connect multiple devices using Rs 232 please reply

What's that db 9 cable

Great

in another video, you say rs232 only connects to one device but here you connect multi-device, I'm confused now realpars?!!

RS 232 is a point-to-point connection. An RS 232 cable can only connect one device to one other device. The connections shown in the diagrams are not possible.

How is RS232 used for multiple devices?

❤

RS-232 is an example of bus?

I'm no authority, but isn't it a RS-232 CABLE and a DB-9 CONNECTOR?

50 feet = 1500cm

Usb: finally a worhy opponent

you completely left out rs232 did NOT start out as a db9 but a db25 just like a parallel connection. not only that, in the beginning they both had female connectors on the back of both pc compatibles and cp/m computers. also 2 computers connected with a crossover or null modem cable can actually be considered a peer to peer network. it may have been slow, but it was much easier than transferring files with floppies by a long shot. if you actually want to learn something then google laplink. if i really want to date myself, i can tell you how i communicated with a mainframe, using a serial modem, a dumb terminal over a straight thru 25 pin serial cable at half duplex. that is why serial is so slow, because it is at half duplex, meaning you could either send or receive data but not do both like a full duplex ethernet connection. do you even know what the anacronym modem stands for? it is modulate demodulate, meaning my modem takes digital information, turns it into an audible tone that gets sent over a phone line, then your modem hears it, turns it back into digital information and sends it to the computer. i always laugh myself silly when children like you try to explain computer history and completely screw it up. next time do your homework.

Rs-232 does not have multipoint capability.

whoa whoa slow down

thank you