Accessing a Cisco Switch or Router via Serial Port on Linux Using Minicom

If you need to access a Cisco swith or router on Linux (Redhat, CentOS, Debian, etc) then install minicom, and do the following.

Firstly you can check which serial ports on your computer are available:

dmesg | grep tty
ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A

Then run minicom:

minicom /dev/ttyS0

Type:

Ctrl + A Z

Then type ‘o’ (the letter, not number) and select ‘Serial port setup’ to configure minicom. Here is a sample configuration of what you want your configuration to look like:

A – Serial Device : /dev/ttyS0
B – Lockfile Location : /var/lock
C – Callin Program :
D – Callout Program :
E – Bps/Par/Bits : 9600 8N1
F – Hardware Flow Control : Yes
G – Software Flow Control : No

To get to here, please read the following:

Ensure the correct serial port is being utilized by pressing A, the port you will usually be using is /dev/ttyS0

Press E to configure bit rate, then select E again, and then Q and Enter.

Ensure Hardware Flow Control is on, and Software Flow Control is off.

If you are having issues, try exiting and re-opening minicom, or disconnecting and reconnecting your console cable.

Filed under: Uncategorized by — aaron @ 12:25 am