RS232 to RJ45

[goudeuk]

Hello everyone

I have an instrument that is controlled by a computer. The communication between the two is via a very long serial cable. I would like to remove the serial cable and establish a connection using a RJ45 cable. I bought some RS232 to RJ45 adaptors and I wired them using this wiring pinout:
https://www.lammertbies.nl/comm/cable/yost-serial-rj45.html

As you can see, in "DB9 to RJ45 serial adapter wiring diagram", it shows the red and green cables going inside hole 5.
Does that mean that either cable in hole 5 should the job? I tried using only the red cable in hole 5 on both ends (instrument+computer) but it doesn't work.

I only ordered 6 adaptors and once the cables are in the hole they sort of lock and I can't get them out, so I can not try different cable layouts. I have to use a new adaptor each time.

Any suggestions please?

How can I wire the adaptors so the computer and instrument can communicate?

Thank you

 

[kellys_eye]

Why a cable change? What do you hope to achieve by this? RS232 is good for 50 feet or so, potentially further with a reduced capacitance cable (the CAT5 stuff) but 50ft is still an awful long distance!

Either way, the article states:

If twisted pair cable is used with the RJ45 connectors, the following pairs are advised to minimize cross-talk between the lines: 1-2, 3-4, 5-6 and 7-8. When twisting this way, both data lines are twisted with their own signal ground line, adding some noise immunity.

but providing the sending end pinout (however you care to arrange them) matches the receiving end there is nothing else to mention.

If you want to go 'further' then consider changing signal levels completely rather than the cable i.e. protocol conversion.

 

[goudeuk]

The reason is tidiness. There are some new RJ45 wall sockets on the wall which I was hoping to use instead of having a long cable hanging from the ceiling. So, I should try something like this:

RS232--> RJ45 -->Twisted RJ45 --> RS232

I need to find my RJ45 kit.

 

[kellys_eye]

RJ45 sockets on the wall???? Running where? Surely they would be put in as part of a distributed network system and terminated at a 'switch'??

You can get protocol converters that will change RS232 to 'something else' and give an increased range but if this is simply a case of using a convenient cable run you'd better check that the ends are 'free' and not looped into some other system wiring!

 

[goudeuk]

The instrument and the computer are not in the same room. The wall sockets are terminating to the room where the computer is. No network switches are involved.
The reason these were installed (RJ45 wall sockets) is because in that room there are other instruments that communicate with computers via RJ45. So instead of having long cables they are now going through walls. However one instrument is using RS232 and I'm trying to establish a connection through the wall sockets too.

 

[goudeuk]

It works. Twisting the RJ45 wiring on one end did the job.
Many thanks kellys_eye

All the best