A lot of network devices has a terminal RJ-45 socket, which is usually a simple COM-port. So, to configure such a device, you have to connect RJ-45 socket to PC's (or terminal's) DB-9 COM-port. Documentation usually says: "use the terminal cable, provided with the device", and then the awful discovery shows up: "Hmm... uh... terminal cable? That tiny little thing, which I threw out just after buying the device five years ago?"

The only way to patch situation up quickly - to use handmade cable, which you could do in couple of minutes, knowing the propper pinout.

So that is the case, which terminal cable pinouts for such things as CISCO or D-link devices do you know?


I would look at AllPinouts.org under the serial cables category.

Here is the reference for Cisco RJ45 to DB9 connector.

If you ever find out about a cable that isn't listed there you can create an account and add it to the database.

There are other places I have found information about cables.

You could also check out the 5-in-1 Network Admin's cable, if you want you could use a keychain Cross-Over adapter, instead of "The World's Shortest Crossover Cable"

  • I believe, that's not all the pinouts we could find in the NET, but your answer is very best yet here, thank you. – Alexey Shatygin Jun 6 '09 at 8:14

Search for the "5-in-1 Network Admin's cable".

Then you won't need to make another should you stumble across some Sun/Cisco gear in the future.


Yes. When we get a device that has a cable, the cable gets labeled with the serial number of the unit it came with, the date unpacked, and the name of the unit in our nomenclature, and placed on a wall-mounted pegboard with similar cables in the server room. The rule is to NEVER throw one out. Ever.

A sysadmin that used the wrong cable on a very large, expensive KVM bricked the thing while trying to upgrade the firmware. Luckily for him, he kept his job. That has not always been the case.

  • I think, that's not the way to solve the problem. What if you've got broken calbe? Or, if the label is wrong/lost/something? – Alexey Shatygin Jun 6 '09 at 16:17
  • 1
    What, firing the dunce? No, that always solves the problem. ;) We use permanent labeling, and group them by 'class' -- it would be rare that we only have one piece of a particular model. So we've generally got three or four cables of the same type. That way, if a cable breaks, we can use one from a 'close' model and be relatively certain that it will work. Pinouts can change with hardware revs. In the case of the bricked KVM, he used a serial cable from an APC smart power supply on a Belkin KVM. Caused a small release of magic smoke. – Karl Katzke Jun 6 '09 at 16:42
  • Your organisation seems to be very disciplined )) but, I think, there is always a place for emergency situations on our field :) – Alexey Shatygin Jun 7 '09 at 10:39

Cisco provides detailed information about their console cables


  • Ok, it is Cisco, but what about, for example, old-cabletron switches? I spent several hours to find out, that it deals with standard Enterasys cables – Alexey Shatygin Jun 1 '09 at 5:07

I've always used this website as a reference: Zonker's Greater Scroll of Console Knowledge.

While it's far from exhaustive, I've been lucky in that every device I've ever needed to console into has been listed there. Please let me know if you find a better resource; I'm dreading the day when it fails me. :)


They aren't the same. Cisco, HP and APC use at least two separate pinouts.


What may make even more sense than maintaining each and every cable from each device you purchase, all I can assume is that you do not have much of a variety, would be to pin out each of the cables and maintain a record of not only which cable on the pegboard it is used on, but what the actual pinout is so in the event a cable is damaged or lost you can build a new one in 5 to 10 minutes. I would also venture to say that you could keep only one type of console cable (recommend the most frequently used pinout) and use some scrap twisted pair to make adapters for the anomaly systems.

What pains me is that people in our field know so little about electronics they cannot get anything accomplished if they can't find the prefabricated cable that came with the device. All I can say is good luck if your office ever encountered and emergency like a fire, leaking pipe or disgruntled IT administrator (that never happens does it?). I tend to lean towards actually understanding the technology we are paid to support but to each their own.

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