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:

PIN	Color
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 Pin	RJ45 Color
1 2 3 4 5 6 7 8 9	Brown Yellow Black Orange Green -UNUSED- Blue White -UNUSED-

Reference Link