Searching with Google returned only 3rd party documents (i.e. from chip vendors or university lectures). Is there a main document of such specification, similar to USB?

  • \$\begingroup\$ I think it's this (OCLC WorldCat link). Will look for a non-print reference. \$\endgroup\$
    – uint128_t
    Jun 23 '16 at 15:20
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    \$\begingroup\$ Yes, but it is not free. And you might be disappointed that it only mentions connectors, pin names, and voltages, NOT the data format that is used. \$\endgroup\$ Jun 23 '16 at 15:21
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    \$\begingroup\$ Wow.. that's a big score for such a question... \$\endgroup\$
    – Eugene Sh.
    Jun 23 '16 at 17:40
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    \$\begingroup\$ @dim Well, in this case I am not even speaking of the answer, which did require from you some effort. I am speaking about the question, not demonstrating any and not very useful at all.. \$\endgroup\$
    – Eugene Sh.
    Jun 23 '16 at 18:20
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    \$\begingroup\$ @Amumu: Are you serious? The second link for me is the Wikipedia article about rs232, which in the first paragraph states: The current version of the standard is TIA-232-F Interface Between Data Terminal Equipment and Data Circuit-Terminating Equipment Employing Serial Binary Data Interchange, issued in 1997. \$\endgroup\$
    – Eugene Sh.
    Jun 24 '16 at 1:25

The original standard has been written by the Telecommunication Industry Association (TIA). Its name is EIA/TIA-232.

But you must pay to get it. You can buy it on TIA's store. This is the reason why you don't find it on the internet: publishing it is illegal.

Anyway, all the necessary information required to implement an RS-232 device is easily available on the internet and on various 3rd party publications, as you noticed. I guess TIA doesn't make much money from this standard anymore.

(and at this price, I wouldn't buy it)

Here are some useful resources:

  • Linear Tech RS232 Quick Guide, summing up pretty much everything needed from a technical point of view, in a single page.
  • Wikipedia page for more detailed explanations and some historical background.
  • An old app note from Dallas (now Maxim) covering all technical aspects in details.
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    \$\begingroup\$ Wow, a big price tag for such a common standard. I guess the book has nice colors in it. \$\endgroup\$
    – Amumu
    Jun 23 '16 at 16:07
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    \$\begingroup\$ @amumu Colors? For this price people should get an authentic illmuninated manuscript. \$\endgroup\$
    – dim
    Jun 23 '16 at 16:30
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    \$\begingroup\$ @Amumu: Different licensing schemes. The USB spec can easily be found online but manufacturers must pay to buy a vendor ID so that device drivers can identify the device. Also, vendors need to pay an annual fee if they want to declare that their device is USB and use the logo (which is why some generic products form China do not say they're USB even though the connector is obviously USB). RS232 on the other hand has no licensing fee for implementations but make their money from selling the spec (this is the same business model as the PCI bus) \$\endgroup\$
    – slebetman
    Jun 23 '16 at 18:22
  • \$\begingroup\$ Seeing how old serial port is, it still needs a person to pay to get the official specification??? I am surprised. \$\endgroup\$
    – quantum231
    Jun 23 '16 at 22:46
  • \$\begingroup\$ The RS-232 protocols are old, made for QAM transmissions,etc. I see many RS-232 to RS-485 adaptors and even I2C adaptors. Intel has stated that the DB-9 connector will be around for some time on work-stations and desk-tops, but if you write your own code or use LabViews basic drivers, the protocol is what you want it to be. For valid operation RTS and CTS should be used properly. \$\endgroup\$
    – user105652
    Jun 24 '16 at 6:24

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