RS422 standard connector?

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Hi guys,

Is there anything like an actual standard for an RS422 connector? The connector type as well as pinout.

I've done some searching, and everybody seems to use a different pinout on a different connector type. I've seen a lot of devices use a DB9 connector, but the pinouts and gender vary wildly. A lot of them use numbered screw terminals, but again, the pinouts vary wildly.

I'm guessing there's no standard way to do this, but I'd like to be certain.

Thanks,

David

There are pointy haired bald people.
Time flies when you have a bad prescaler selected.

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Quote:
I've seen a lot of devices use a DB9 connector,
One of my project used a laser sensor which used a DB9 RS422.
Pin Signal
1 RX 
2 Tx +
3 TX 
4 NC
5 GND
6 NC
7 NC
8 NC
9 Rx +

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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I looked into it some years ago when I was using RS-422, and couldn't find a standard connector. I used a DB-9, like John.

Leon Heller G1HSM

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Thanks for the info guys. It's for the best as I can add another signal (power) onto the port.

There are pointy haired bald people.
Time flies when you have a bad prescaler selected.

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Adding power on the connector will Introduce the possibility of it being wired incorrectly. If the voltage exceeds the specs for the driver chips and it ends up connected to the 422 data lines then the drivers will die. My stuff incorporates protection for this possibility.

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As far as I know, there is no standard connector. Actually, there is no standard connector for RS232, either. For many years, people treated DB25 as standard; now it is DB9. But, neither is mentioned in the RS232 standard!!! These are "standard by consensus".

I've used RJ45 (4 contact) for years with RS422 and RS485.

Jim

Jim Wagner Oregon Research Electronics, Consulting Div. Tangent, OR, USA http://www.orelectronics.net

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@Kartman: Thanks for the warning, but I've already got overvoltage/reverse polarity/ESD protection on everything that goes in or out of the device.

@ka7ehk: Interesting! Thanks for the info!

There are pointy haired bald people.
Time flies when you have a bad prescaler selected.

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js wrote:
Quote:
I've seen a lot of devices use a DB9 connector,
One of my project used a laser sensor which used a DB9 RS422.
Pin Signal
1 RX 
2 Tx +
3 TX 
4 NC
5 GND
6 NC
7 NC
8 NC
9 Rx +

And that you are caling "RS422"? I would rather call it RS485.

HM

HM

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Quote:
And that you are caling "RS422"? I would rather call it RS485.

RS422 has a tx and rx pair whereas RS485 usually has only one pair that is half duplex however there is '4 wire rs485' that has a rx and tx pair, but the tx pair is multidrop. Not sure if 4 wire is actually part of the 485 spec and people have argued with me but I've not bothered to pay money for a spec just to prove a point that can be researched easily on the web.

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ka7ehk wrote:

I've used RJ45 (4 contact) for years with RS422 and RS485.

Jim

Isn't that RJ11, as RJ45 has 8 contacts (Ethernet cables)?

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Quote:
And that you are caling "RS422"? I would rather call it RS485.
No that's what the manufacturer of the product (Micro-Epsilon Germany) are calling RS422. :)

RS485 is bydirectional and can be multimaster and can have 32 or more nodes. RS422 is unidirectional on each pair of wires TX and RX (1 master and up to 10 slaves)

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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Actually there is supposed to be a "industry standard" pinout for RS422/485 DB9 connectors, you may find the pinout at the datasheet of the FTDI USB to RS422 converter modules, like this one

http://www.ftdichip.com/Support/...

Hope that helps.

So, now I know how ICs work:
they work with smoke.
Cause every time you let the smoke come out of an IC, it stops working.
I can prove it, too...

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See JS, I told you aor_dreamer was good for something! :)

"I may make you feel but I can't make you think" - Jethro Tull - Thick As A Brick

"void transmigratus(void) {transmigratus();} // recursio infinitus" - larryvc

"It's much more practical to rely on the processing powers of the real debugger, i.e. the one between the keyboard and chair." - JW wek3

"When you arise in the morning think of what a privilege it is to be alive: to breathe, to think, to enjoy, to love." -  Marcus Aurelius

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larryvc wrote:
See JS, I told you aor_dreamer was good for something! :)

8)

So, now I know how ICs work:
they work with smoke.
Cause every time you let the smoke come out of an IC, it stops working.
I can prove it, too...