[SOLVED] RS232 standard and pins in DB9 connector

[barry]

Well said Klaus!

The same wrong information is being repeated by people who will not read our replies.

Brian.

I second that. I just gave up. I suggest the OP pretty much ignore everything said here and go read some documentation online; there’s plenty of it.

 

[KlausST]

Hi,

I'm not sure whether RS232 defines connectors and pin numbers at all.

Klaus

 

[ads-ee]

Hi,

I'm not sure whether RS232 defines connectors and pin numbers at all.

Klaus

I'm pretty sure it specifies the pinout for 25 and 9 pin connectors, but I'm not certain if it specifies the dimensions of the physical connector. Though I haven't seen a copy of the standard itself in the last ~30 years.

Maxim Integrated, TI, etc have published documents on the standard (to help someone to use their parts), which is probably a better (and more accurate) source of information than forum posts.

 

[c_mitra]

I'm not sure whether RS232 defines connectors and pin numbers at all.

I think it does; but I have not seen them for a very long time.

The standards are not available online.

If my memory serves me right, the 9 pin connector DE-9 (DB9 is the same DB25 connector but only 9 pins present) was introduced by IBM for the IBM-PC.

The same connector DB25 was also used for the printer port (parallel port) but with a different connector at the printer end.

The 3-wire connections came with microprocessors; they are not part of the standard. (also the DE9 connector pinout)