When you need to connect a cisco router or a switch to a windows machine you can use the windows default dialer called hyperterminal. But connecting your cisco router or a switch can be hassle as there is no default dialer present in linux.
There is a way to connect your cisco switch or a router to linux using a third party dialer called MINICOM.
Read step by step How To Connect A Cisco Router / Switch to Linux Terminal Using Minicom
I am assuming you are using ubuntu linux. If not you can download MINICOM from here.
Step1.) Install Minicom in your ubuntu linux.
sudo apt-get install minicom
Step2.) Now you have o find the serial device which is your cisco router or a switch. Type the following command.
dmesg | grep tty
Step3.) Now open Minicom ( you might need superuser privileges)
Step4.)You need to configure your minicom first to be able to use it with your cisco router/switch.
press ctrl +a . Now press Z
Now Press "o" ( Not zero)
Choose serial port setup from the screen.
Now press "A" .Type the device name you got from the dmesg | grep tty command.
Now press enter.
Now press "E" to set the bits per second. Press "E" again to set bitrate to 9600.
Set hardware control flow to "YES" and Software control to "NO".
Press enter and quit. Restart minicom and you should be able to connect to your cisco router/switch on any flavor of linux.