What does DB stand for????? 1

[lgebhart]

I have heard several different answers for this and I would like to know what yours are. When you see DB-9 we know it is a 9 pin serial port, but what does the DB actually stand for???????

TIA,

Lori ggebhart@clover.net
I hope I never get too old or arrogant to learn something new!

 

[Daveyboy2]

Da Bears! (Only in Chicago)

Darn good question.

I always forgot what DOS stood for - I always said it was Da Operating System.

 

[GoLdFiNgeR]

data bits ??????

 

[benzito]

DB stands for Data Bus.

 

[ANFPS26]

DOS is "disk operating system" "A little knowledge is a dangerous thing....."

 

[dinosnake]

Well, the 'D' in DB-9 stands for the shape of the shell. If looked at directly it resembles the letter 'D'. The '9' stands for the number of pins. The 'B'? Good question. The exact details seem somewhat lost in history, but I think it might mean 'binary' - the data type transmitted over the wires. It could also mean 'Bell' - AT&T was instrumental in developing it.

Anybody else remember any details? Your mileage may vary...

 

[hotfusion]

Yes: The suffix 'M' means male, And 'FM' means female.....P-)

O.k., I added this simply for the sake of completeness..... My suggestions are what I would try myself. If incorrect, I welcome corrections to my rather limited knowledge. Andy.

 

[edfair]

The "D" is for the shell. The "B" is for the form factor, not followed by all manufacturers, where "B" is for 25 pin, and the possible choices are "A" through "E". And the suffix "P" for plug or pin and "S" for socket.
Ed Fair
unixstuff@juno.com
Any advice I give is my best judgement based on my interpretation of the facts you supply. Help increase my knowledge by providing some feedback, good or bad, on any advice I have given.

 

[dinosnake]

Thank you. But, with all respect, I'm still not sure about the 'B', as the RS232 standard lists a DB9 as a possibility. So the 'B' cannot be just for 25 pin.

Yeah, it can be 'P' or 'M' for plug / male or 'S' or 'F" for socket / female. That seems to depend on the nomenclature of the manufacture of the part. The p/s option seems to apply more to solderable board-mount parts, while m/f seems more common on inline connectors.

Your mileage may vary...

 

[Eguy]

I always thought it was Danny Bonaduce

Ed Please let me know if the suggestion(s) I provide are helpful to you.
Sometimes you're the windshield... Sometimes you're the bug.

 

[edfair]

That is one of the manufacturers that didn't follow the standard. Should have been a "DA9". I've never seen a 232 spec sheet that specified a connector, just defined the signal levels and names of the signals.
And if you think that RS232 is a standard spend some time dealing with different manufacturers communications equipment. At least transmit, receive, and common are well defined. And if they screw it up you can figure it out pretty quickly with a VOM. Ed Fair
unixstuff@juno.com
Any advice I give is my best judgement based on my interpretation of the facts you supply. Help increase my knowledge by providing some feedback, good or bad, on any advice I have given.

 

[dinosnake]

Very true. That why they converted the RS232 'standard' to the EIA232 standard - to try to get a standard 'standard'.

Oh, well. But then again, getting TTL voltage out of box to do anything sometimes is a miricle. I assume that a few of the problems you've had are timing related across the cable-distance caused impedence load? The standard might be there but nobody said that they had to make quality cable to help conform to it...

The standard does specify the DTE Device Connector - the DB25 and optionally the DB9. Of course, the DB9 is a 'quicky', cheap bastardized version of the DB25. Why pay for pins you (usually) don't use?

I think this is one of those things that we'll have to dig up from some grave one of the original guys who was hanging around while things were getting set up to find out the truth.

I still wouldn't be surprised if the B refers to Bell - have you ever taken an old mechanical desk phone apart? Inside is a connector running to the main patch bus - a DB25. I have personally never seen a reference for a DA25 - but that, of course, doesn't mean squat in a barnyard.


Your mileage may vary...

 

[edfair]

AFter thinking about it a while, the 9 pin was DE. Ed Fair
unixstuff@juno.com
Any advice I give is my best judgement based on my interpretation of the facts you supply. Help increase my knowledge by providing some feedback, good or bad, on any advice I have given.

 

[edfair]

http://epl.meei.harvard.edu/Engineering/d-subminiature.html

Ed Fair
unixstuff@juno.com
Any advice I give is my best judgement based on my interpretation of the facts you supply. Help increase my knowledge by providing some feedback, good or bad, on any advice I have given.

 

[lgebhart]

Ed,

This is what I was looking for something in black and white that I can show my students. I have done various searches myself but have never come across the link you just sent!

Thanks a million!

Thanks also to the others who have posted their great replies!



Lori ggebhart@clover.net
I hope I never get too old or arrogant to learn something new!

 

[dinosnake]

Yes, but if you look at other areas, for instance:

http://www.pcwebopaedia.com/TERM/R/RS_232C.html,

and use the link to:

http://www.rad.com/networks/1995/rs232/rs232.htm

specifically:

http://www.rad.com/networks/1995/rs232/pins.htm#g1

the RS-232 D EIA standard specifies DB-25 connections only as meeting the specs. The old RS-232 C standard did not specify mechanicals, but when brought into the EIA fold the mechanicals were assigned for compatiblilty. Now, the standard specifies 'DB25' with the possibility of 'DB9' for maintaining the compatibility with PC's, which were already intrenched with the DB9 even though it did not meet any standard. The de facto DB9 was, at least, acknowledged.

Many statements regarding the standard all mention DB9 if speaking about that configuration. What's going on? Is it that the part manufacturers settled on a de facto of their own? I wish I knew... Your mileage may vary...