I am aware of the RJ-45 to DB9 adapter commonly used on cisco routers to access console. I am aware of the USB to DB9 adapters to allow laptops without serial to get a serial port. I am looking for a USB to RJ-45 adapter so I don't have to chain two adapters together. I have searched everywhere but even the pre-packaged solutions seem to have the two adapters chained together. Does such a thing exist? If it doesn't is there some technical reason it cannot? It seems like a manufacturer would just have to wire the DB9 end of the USB adapter differently and it would work just fine plugged straight into the console port of the router.

6 Answers 6


I haven't seen one. It would have limited usefulness as Juniper, Cisco, Linksys, APC, HP Procurves, our Raritan power strips, etc all use different cables -- and some use different baud rates.

We've got a box of cables in our cage labelled with the baudrate/connection protocol and devices that it works with.

It is technically possible. I don't see it as being a big seller though.

  • 1
    There are a bunch of them that exist now (2016).
    – demure
    May 20, 2016 at 19:10

If there is still interest I produce a cable assembly to do just this. As for the need to have a box of cables for different devices and each of them labeled with the communication protocol and baud rate I am at a loss for words. The baud rate and communications protocol utilized by a specific device has nothing to do with the cable the data is transmitted on. I have a feeling that if you took the time to actually pin out all of the cables you use to support your equipment you will likely find (2) pinout variations when the cable is terminated to an 8P8C (typically though incorrectly referred to as RJ45). It is also very likely that any of you devices which have a DB9 male connector mounted in the panel of the device can be accessed through the use of a null modem and console cable. This of course would mean the vast majority of the cables could be discarded and only the communication protocols/BAUD rates be retained but I am sure maintaining numerous cables in a box gives someone a purpose and feeling of importance.
All hail inefficiency!!


I highly doubt there is enough demand to make the a USB to Cisco Console cable adapter worth selling.

But there is no reason that it couldn't be done. With a little hardware hacking you could build your own.

  • @Andrew, not sure why you made an edit that changed the meaning to make it sound more difficult. Obviously it isn't just a trivial change. But is also is not that difficult. Just take a usb-serial adapter, remove the db9 and added a RJ-45. The RS-232 and Cisco pin-outs are very well documented online.
    – Zoredache
    Jul 1, 2010 at 5:42
  • {{sofixit}}?
    – Andrew
    Jul 1, 2010 at 6:44

It has been made and is now available at http://www.get-console.com/shop/en/18-usb-to-serial-cables - yes a VERY niche product no doubt, but you can convert it back to DB9 serial with a RJ45-to-DB9 dongle as well. It has native driver support for OSX and Win7/8

/Shameless plug


There is one here http://www.diablocable.com/diablo-cable-6ft-usb-to-rj45-rollover-console-cable-for-cisco.html as well and looking at its picture it features and in-cable electronics box which should do the trick right.


Yes it does. Diablo cable has 6 and 10 foot. Works natively with windows 8, no need for drivers unless you have earlier windows.


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