RS-232/485 Serial Port

[Engineer_UA]

Hello,
Can a single DB-9 or mini-DIN8 port be used to interface with RS-232 or RS-485 serial connections?
Thanks,
EE

 

[danw]

It depends on the hardware behing the physical connector pins. No way to answer your question without knowing what the active serial hardware is.

Further, the complexity of the hardware determines to what extent communications are doable. The 3 wire RS-232 point-to-point connections would not operate a 1991 telephone modem at 5400 baud that needed hardware flow control, because those hardware connections are missing.

 

[Ken Roach]

There's no enforceable standard that prohibits a device manufacturer from putting whatever signals they want onto a DB9 or Mini-DIN8 connector pins.

You'll find lots of HMI vendors who cram multiple signal port types into a single connector (hello, Red Lion !) an occasionally PLC vendors too (Channel 0 on a MicroLogix 1100/1400).

 

[parky]

I agree with Ken, because it is a DB9 does not mean it is RS232, or even 4 pin strait connector could be any of the types.
For some examples some PLC's have a mini din but depending on the model it could be RS232, 422, 485.
Even what could be mistaken for ethernet ports could be any type again for example the old SLC500 has one but it is not ethernet,
Many HMI's have multiple ports, some use a DB25 where there are 232/422/485 on the one connector depending on the pins you connect to.

 

[Corsair]

Ever see the phrase 'standard serial data cable'? There is no such thing!

There are DB-9 cables that are pinned all 9 straight through. Anything else requires a diagram or an ohm meter. Unless the cable manufacturer made it specifically for your application with the equipment that you are using. Even a 'Null Modem' cable could be made with or without handshake connections.

 

[widelto]

I have seen rs232 and rs485 on RJ45 , powerflex dives are good example for rj45 with rs485 and Cisco data switches are another example for rj45 with rs232