I've looked under every search term on google I can think of and can't seem to find anything that works.

I just switched from Windows 7 to Fedora 15 on my PC. I need use of the console port to interact with Cisco switches and other devices. However, I cannot seem to get it to work. I've tried putty, and it says :

Unable to open connection to:
Unable to open serial port

I've tried minicom as well. Both putty and minicom I set up to /dev/ttyS0. I did have it working, once, connected with cat /dev/ttyS0, and it outputted the info from the switch, but when it got to the point where the switch expected input, it looped the input request message dozens of times a second.

I thought it might be a driver issue, but I cannot find any info for getting drivers for serial ports. I'm thinking I probably need to know the adapter model # or something. The port is built into the motherboard though, so I don't know if it has one.

I also tried setserial /dev/ttyS0, but it gives the message:

/dev/ttyS0, UART: 16550A, Port: 0x03f8, IRQ: 4

Is there a command to get info about the serial port/adapter? Is there something that I am doing wrong that I am not seeing?

  • For me, I used the serial/usb converter for my console cable. I had to change the /dev/ttyS0 to /dev/USB0.
    – user14562
    Jan 20, 2012 at 20:16

2 Answers 2


It sounds like you may have the flow control settings wrong - did you play around with Hardware and Software flow control? The would be in the minicom setup.

  • I tried changing both those settings, and it did not help. I did get the console port working with putty, turned out the problem was that my user didn't have access to the ttyS0 interface. I added my user to the appropriate group and that fixed putty. It did not make a difference in Minicom though Jul 28, 2011 at 17:39
  • if minicom set to 9600 8N1 ?
    – Sirex
    Nov 23, 2011 at 11:28

minicom for sure will work. screen /dev/ttyS0 is practical as well.
Just make sure you have read/write permission for for the according tty like Asher said

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