How to use the FTDI USB serial cable to RJ45 adapter to connect to the console on Cisco/Juniper Switch Router Firewall in Linux Ubuntu Debian Redhat

This should work for most console ports of other manufacturers too.  It is a quick and simple method for emegencies or deploying a few appliances/devices in a non-standard environment or small environment. 

However, if this is a route thing, or the equipment is not physically close to you, it would be best to use some sort of "Terminal" server which is an IP connected switch with several serial ports built-in for this purpose.  Normally they accessible by web/ssh/telnet, so you don't have to worry about getting physical access to the device (eg. if it's in a communications room, datacenter or another place that is not convenient to physically access).

Step 1 - Just plugin the USB side and then connect to the console port of the device

The console port is often located at the back of the device, but some devices may have them at the front of the unit.  Also be careful that you don't connect it to the Management port of the device, as then this won't work and you won't receive any output to the terminal.

You should get output like this after plugging in the USB to RJ45 adapter:

[ 2113.427366] usb 1-1.2: new full-speed USB device number 24 using ehci-pci
[ 2113.542286] usb 1-1.2: New USB device found, idVendor=0403, idProduct=6001, bcdDevice= 6.00
[ 2113.542289] usb 1-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 2113.542292] usb 1-1.2: Product: FT232R USB UART
[ 2113.542294] usb 1-1.2: Manufacturer: FTDI
[ 2113.542295] usb 1-1.2: SerialNumber: A50285BI
[ 2113.544859] ftdi_sio 1-1.2:1.0: FTDI USB Serial Device converter detected
[ 2113.544901] usb 1-1.2: Detected FT232RL
[ 2113.545854] usb 1-1.2:
FTDI USB Serial Device converter now attached to ttyUSB0

Note the "attached to ttyUSB0" part, normally a standard serial cable would be available by deault on /dev/ttyS0, but with the USB adapter it will live on /dev/ttyUSB0

If you don't get the above output, confirm that the ftdi_sio kernel module is loaded.  If it's not there, you may need the following packages:


Here is the easiest way to install the missing ftdi driver on Debian/Ubuntu/Mint

sudo apt install linux-modules-extra-`uname -r`

Step 2 - Connect to the console port on your device using screen/putty or other tool

One of the easiest tools to use is screen or putty, but any serial/terminal program will normally do the job.

screen /dev/ttyUSB0

Below is an example of consoling into a Juniper switch.



ftdi, usb, rj, adapter, console, cisco, juniper, router, firewall, linux, ubuntu, debian, redhatthis, ports, manufacturers, method, emegencies, deploying, appliances, devices, quot, terminal, server, ip, accessible, ssh, telnet, eg, communications, datacenter, plugin, located, output, plugging, ehci, pci, idvendor, idproduct, bcddevice, mfr, serialnumber, ft, uart, manufacturer, bi, ftdi_sio, converter, detected, rl, ttyusb, deault, dev, ttys, putty, easiest, consoling,

Latest Articles

  • How to resize a pdf without losing much quality in Linux Mint Ubuntu Debian Redhat Solution
  • qemu: could not load PC BIOS 'bios-256k.bin' solution
  • Proxmox How To Custom Partition During Install
  • Hyper-V Linux VM Boots to Black Screen, Storage, NIC Not Found Issues
  • Ubuntu Mint How to Fix Missing/Broken /dev and /dev/pts which causes terminal to immediately close exit and not work
  • How high can a Xeon CPU get?
  • bash fix PATH environment variable "command not found" solution
  • Ubuntu Linux Mint Debian Redhat Youtube Cannot Play HD or 4K videos, dropped frames or high CPU usage with Nvidia or AMD Driver
  • hostapd example configuration for high speed AC on 5GHz using WPA2
  • hostapd how to enable and use WPS to connect wireless devices like printers
  • Dell Server Workstation iDRAC Dead after Firmware Update Solution R720, R320, R730
  • Cloned VM/Server/Computer in Linux won't boot and goes to initramfs busybox Solution
  • How To Add Windows 7 8 10 11 to GRUB Boot List Dual Booting
  • How to configure OpenDKIM on Linux with Postfix and setup bind zonefile
  • Debian Ubuntu 10/11/12 Linux how to get tftpd-hpa server setup tutorial
  • efibootmgr: option requires an argument -- 'd' efibootmgr version 15 grub-install.real: error: efibootmgr failed to register the boot entry: Operation not permitted.
  • Apache Error Won't start SSL Cert Issue Solution Unable to configure verify locations for client authentication SSL Library Error: 151441510 error:0906D066:PEM routines:PEM_read_bio:bad end line SSL Library Error: 185090057 error:0B084009:x509 certif
  • Linux Debian Mint Ubuntu Bridge br0 gets random IP
  • redis requirements
  • How to kill a docker swarm