Bob's Notepad

Notes on projects I have done and things I have learned saved for my reference and for the world to share

Thursday, January 03, 2008

Pinouts for CAT5 to DTE RS232

If anyone has ever worked with a router or switch from Foundry Networks, then you know how difficult it is to get into the RS232 console port using the standard cables that you usually have available. This is because Foundry is one of the few companies that use a straight through cable rather than the crossed cable that almost everything else uses. Tonight I was working on installing an avocent cyclades CS4016 to connect to the serial consoles on all of our routers. Using the ADB0039 dongles for our Cisco routers worked just fine but the ADB0036 dongles didn't work for our foundry routers and the reason for this is those dongles expect a Yost "flat" RJ45 cable which connects pin 1 to 8, 2 to 7, etc. This is similar to a CAT5 cable except that CAT5 connects pin 1 to 1, 2 to 2, etc. I had access to RS232 DB9 modules so I worked out the pinouts that I needed to use to make an RJ45 to RS232-DTE adaptor using a CAT5 cable rather than the yost flat cable. It's not rocket science but it took a little bit of thought especially when your mind got the interference of too many options for blue, green, etc :)

Anyway, I know that I will need this again so I'm putting it here so I can find it and maybe I'll help someone else out too. These colors are assuming that your DB9 blank modules have the standard Yost coloring.

Standard Yost module on the RJ45 side:

PINColor

1

2

3

4

5

6

7

8


Blue

Orange

Black

Red

Green

Yellow

Brown

White


Essentially all that we are doing is flipping that around. Ultimately we will end up with the following colored cable going into these pins:

DB9 PinRJ45 Color

1

2

3

4

5

6

7

8

9


Brown

Yellow

Black

Orange

Green

-UNUSED-

Blue

White

-UNUSED-

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2 Comments:

Blogger Jason said...

Using the pinout on your page I can get the console to come up, but it is sluggish and doesn't recognize all the characters when you type them in. I am using a foundry MLX router and Cyclades TS-3000 console server. Do you have any ideas I can try to solve this problem?
Jason

11/2/08 7:01 PM  
Blogger Bob K Mertz said...

Sorry for the late response.... Hopefully you've fixed this by now. I would think it might be related to console settings and/or a poor connection on one of the pins. Not really sure above that tho.

10/11/09 1:03 PM  

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