×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

RS232 - DB9 to RJ45 adapter pinout

RS232 - DB9 to RJ45 adapter pinout

RS232 - DB9 to RJ45 adapter pinout

(OP)
I am trying to connect a General Electric PQM (Power Quality Meter) to a PC. I had it connected to a laptop via DB9 null modem cable, and it was working fine, but needed to run it permanently to a PC. I have two DB-9 to RJ-45 adapter's, the female is at the PC and the male at the PQM. There are only a few hundred pinouts for this on the internet but I havent had any luck finding anything that works. I know it should be simple and for most of you I'm sure it is but I am running out of hair to pull out and could use some assistance. I just need the pinout for the two DB9 to RJ45 adapters and should I use a straight through RJ-45 cable or crossover, but I guess it depends on if the wires cross in the adapters. Please anyone....HELP!!!
Replies continue below

Recommended for you

RE: RS232 - DB9 to RJ45 adapter pinout

This always works for me.

If the connection is a straight through, (as in a modem cable type connection):

Both DB9 adapters are to be configured as follows- the yellow wire is inserted into pin 2, the black wire is inserted into pin three, the red wire is inserted into pin 5. The connector on the GE PQM side should have pins 4&5 (RTS/CTS) shorted, (if required). If the adapter does not come with a separate shorting jumper wire, you can cut some of the excess wires off and solder a jumper together. This will allow you to use a standard ethernet cable (straight through), even if it is only configured with four wires.

If the connection requires a null modem connection, reverse the yellow and black wires on one of the connectors.

If you require handshaking between the PC and PQM, use any two unused pairs in the connectors, inserted in pins 4 & 5, and swap the colors on one connector.

I hope this helps.

RE: RS232 - DB9 to RJ45 adapter pinout

(OP)
It's up and running like a champ...Thanks robertjo24 !!!
I was trying to overcomplicate the situation the whole time. Thanks again!

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login



News


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close