Low profile RS232-DB9

A surface-mount socket with some other mechanical support can be just as strong as through-hole -- frankly I'd be suspicious of a DB-9 through-hole that didn't have screws or at least clips.

Do you have to use a DB-9, or just a nine pin thing? There are some pretty small connectors out there if you're willing to step away from the older standards.

--

Tim Wescott
Wescott Design Services
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Honestly I HATE the DB9 connectors and I'd happily do away with it. However Serial cables are the most widely available for PC-device (no I can't do USB unfortunately).

what others do you suggest? I only need 2 wires rx/tx ?

Tim Wescott wrote:

And ground. I used a 1/8" stereo headphone jack in one of my projects. I picked up a few 1/8" to DB-9 cables at the junk store so it all worked out. And don't top post. My cat hates that.

Well, three -- rx, tx and ground.

If it doesn't need to be exposed to the outside you can use anything you want -- I often use a four- or five-pin header, and make up a matching cable.

Modular telephone jacks are a popular choice for compact equipment that needs to run on serial. You still have to make up a matching cable, but it's done all the time.

If you absolutely positively have to be standard, then you just have to use a DB-9, and let the tail wag the dog, of course.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Posting from Google?  See http://cfaj.freeshell.org/google/

"Applied Control Theory for Embedded Systems" came out in April.
See details at http://www.wescottdesign.com/actfes/actfes.html

3.5mm audio (microphone type) jacks are a common alternative to the DB-9. A few minutes with a Digikey catalog should produce some adapter cables which will give you the most common pinouts. Another advantage is that they're cheap compared to a DB9.

Chris

What about using a PS2 (female) connector on your board Connections Tx, Rx, Gnd & +5v standard as per PC mouse interface.

Then also do the following.

Leave the TTL RS232 level shifter (MAX232) off the board and obtain some of the MAX232 wired into the connector shells. see

This cable is expensive but one normally only needs a few. Cable with MAX RS232 can probably be obtained at $10-$15. Replace the cable with a PS2 extension cable. Cut the female socket off the eaxtension and wire the

9-Pin shell with MAX 232 onto the cable. This TTL RS232 cable can be very short and you can still use a long RS-232 extension.

The onboard serial interface is much cheaper without MAX 232 and caps.

The PS2 (miniature DIN) is not the most robust connector but I haven't seen reports of connector failures on PC mother boards.

Gerhard van den Berg CSIR

We use a 2.5 mm stereo headphone jack for RS-232 on several of our instruments where we don't have room for a D9, like this one:

And then we make extra bucks selling the adapter cable!

John

You work for M$ ?

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Many small devices use a stereo 1/8 jack as the connection for RX/TX and common.

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"I'm never wrong, once i thought i was, but was mistaken"
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I think the modular phone plug is a better idea. What I don't link about the stereo phone plugs is they tend to short upon insertion. Granted, the short is momentary.

The RS-232C spec did not specify a connector or pin assignments for any particular connector. (And anyone whose ever tried to attach "anything serial" to a Kaypro already knows this!!)

So basically, you can use whatever connector you like. But when you make the selection, try using something that won't be confused with some other standard. For example, it would be a poor choice to use a USB-style cable for RS-232C, although technically, that would not violate the RS-232C standard.

Later editions of 232 attempted to standardize the physical interface, but by then, the genie was out of the bottle. Others here have given you some good ideas. I would have to concur with the surface mount comments. 9-pin 232's get a lot of user abuse. Keep that in mind.

-mpm

Actually, in the original official RS232C spec, you could short any pin to any other pin for as long as you wanted and it would cause ZERO damage to the hardware. (Look it up!)

It wouldn't work of course, but you were essentially guaranteed you wouldn't blow anything up!

Now that said, we all know there were lots of products that weren't "truly" RS232 compatible....

-mpm

There are NO DB9 connectors. The proper designation is DE9.

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Michael A. Terrell
Central Florida

I've never heard of rs232 being damaged by a short-circuit

I've seen some equipment use a 1mm pitch 3x2 pin header, atleast I think it'a a serial port, the actual label is "console" - it's on a linux based ADSL modem.

--

Bye.
   Jasen

The only times I've seen a MC1488 or 1489 fail were during an electrical storm. (none of my dodgy serial cables eved damaged anything)

I never connected mains voltages to a serial port though - did the naval ones need to withstand something like that?

Bye. Jasen

The worse thing you can do is have messy cables where the serial cable happens to wrap around or be in line with the AC cables during a near by strike. the induced currents will transfer to the serial and over load it. I for one, lost 2 keyboards this way..

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"I\'m never wrong, once i thought i was, but was mistaken"
Real Programmers Do things like this.
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Well, you've got me on that one - maybe for that they depended on the difference in connectors. In any case I know they were terribly robust, because they were designed to be used on a Navy ship, and survive under combat conditions.

Thanks! Rich