How to connect to a Cisco router via the console cable

You have a Cisco device (router or switch) and you want to connect to it via the console cable, but you do not know how to do this. In this post, I will show you the step-by-step process.

Buy a USB console cable

In my example I will use a USB console cable. You can buy a similar one from here.

Cisco console cable USB to RJ45
Cisco console cable USB to RJ45

Connect the console cable to your router

After you have the console cable, the next step is to connect the USB end of the cable to your computer and the RJ45 end of the cable to the Cisco router. On the router or switch you will find a port which is labeled as console. You can find an example below. In my lab, I use a Cisco 2911 Router. The model of the router or switch does not matter. You need to take the same steps.

Cisco 2911 Router
Cisco 2911 Router

Turn on the router

After the cable is connected, you need to turn on the router. There is a power switch on the router. You do not have one on the Cisco switches. The Cisco switches are starting to boot as soon as you plug them to the power outlet.

Cisco 2911 Router - Power Switch
Cisco 2911 Router – Power Switch

Check the allocated TTY port

After the router is up and running, you need to check which TTY port was allocated by your operating system to the USB port where the cable is connected.

Run this command:

sudo dmesg | grep -i USB | tail
Finding the allocated TTY port
Finding the allocated TTY port

A similar command which gives us approximately the same result is:

ls -l /dev/*USB*
Finding the allocated TTY port - second method
Finding the allocated TTY port – second method

Install the required software and configure the connection

Now, you need to configure the connection and start it. You can use two methods for this.

Method 1: Using Minicom software

You need to install minicom because it is not present by default on the Ubuntu host.

Run the command:

sudo apt-get install minicom
Install minicom
Install minicom

Configure minicom

After the minicom package is installed, you need to configure the connection.

sudo minicom -s
Enter configuration mode
Enter configuration mode

Go to the serial port setup. You need to use the Up and Down arrow keys.

Serial port setup
Serial port setup

Specify the serial device by pressing A and add the details from “Check the allocated TTY port”step.

Specify the Serial Device
Specify the Serial Device

Specify the Bps/Par/Bits by pressing the E key and select the option C. You need to use the speed 9600.

Specify the speed
Specify the speed

Change the hardware flow to no. Press the F key to change it from Yes to No.

Change the hardware flow control
Change the hardware flow control

Press the Esc key to go to the main window. Here you have the possibility to save the changes. Select the option Save setup as DFL and hit the Enter key.

Save setup as dfl
Save setup as dfl

The last step is to press Exit. Now you can start configuring your device.

Exit from configuration mode
Exit from configuration mode

Here you can see the output from my Cisco router.

Explore and configure your router
Explore and configure your router

Method 2: Using Screen software

The same result can be achieved by using the screen program.

First, you need to install it with the below command:

sudo apt-get install screen
Install screen
Install screen

After the screen software is installed, you need to open the program and specify the connection speed to 9600. Don’t forget to hit the Enter key.

screen /dev/ttyUSB0 9600
Start the screen program
Start the screen program

Now, you can start to explore and configure your Cisco router.

Explore your Cisco router
Explore your Cisco router

Connect your Cisco router via the console cable on your Mac

If you do not use Linux, but macOS, there is no need to panic. The same process applies to your Mac.

The first step is to identify the TTY port.

ls /dev/*usb*
Identify the TTY port
Identify the TTY port

Now, you just need to run the screen program. The screen package is installed by default on your macOS.

screen /dev/tty.usbserial-A50285BI 9600
Start the screen program
Start the screen program

Now you can start configuring your router.

Configure your router
Configure your router

Connect your Cisco router via the console cable on your Windows host

If you use Windows, the process is somewhat different.

You need to download the Putty software. You can find the link here.

Download Putty
Download Putty

The next step is to install the downloaded software. Double click on the putty-64bit-0.78-installer.msi and press Next until the installation process is completed.

Install Putty
Install Putty

Now, you need to open the Putty application.

Open Putty
Open Putty

The next step is to identify the serial port allocated by Windows to your USB cable. Open the Computer Management console. Go to the Device Manager. Check the Ports. In my lab, Windows allocated the COM3 port to my USB cable.

Computer Management
Computer Management

Return to the Putty application, select the connection type as Serial and specify the allocated port. I added COM3.

Select the connection type
Select the connection type

Next, press the Open button and start configuring your device.

Configure your device
Configure your device
How to connect to a Cisco router via the console cable on Ubuntu
How to connect to a Cisco router via the console cable on macOS

I hope you find this post useful.

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