Hello all. I recently installed Xubuntu 14.04 onto one of my extra computers, and I am attempting to access some of my Cisco equipment using a Serial-to-USB adapter and the standard Cisco rollover cable.

I have read through MANY how-to's online and have followed all of them verbatim to try to get this working, and still no luck. I have verified that my serial device is listed as ttyUSB0 and have successfully installed minicom 2.7. I appropriately adjusted settings to 9600bps, with parity/data/stopbits set to 8-N-1 and disabled flow control.

When I attempt to connect to a Cisco device, minicom loads properly, but then begins to display unreadable characters. (The characters look like rectangular boxes with tiny illegible letters inside the boxes) I have tried everything I can think of to get this to work, but I just cant figure it out. If anyone can help, that would be greatly appreciated.

Should be a no brainier...

You did not mention model numbers but are you connected to the console port vs aux port?
With non ASCII characters being displayed my first thought would be to go back and verify the settings again.

You can jumper pins 2-3 (loop back) on the USB serial connector and verify that what you see is what you type. Will not verify settings since receive and send will be set the same.

The unreadable characters clearly indicates that Minicom is receiving something, just not a data stream it's able to make sense of. Are you sure both the serial cable and the USB adapter are working correctly?

The speed of the serial port on Cisco equipment can be changed by manipulating the configuration register. Are you sure this particular router is still using 9600/8/n/1? Have you tried other speed settings in Minicom?

@michaelk -
I have tried both 2950's and 2651XM's, switches and routers. I am utilizing the console port on the cisco equipment. I have checked and double checked the settings of minicom with no luck.

@Ser Olmy -
Yes, minicom is certainly reciving something, and based on when and how the non-readable characters are showing up, it seems to indicate the normal boot patern of the cisco IOS. Both my windows 7 and 8 machine are able to communicate with these devices using the same usb-to-serial adapter cable and rollover cable utilizing either putty or teraterm at the speed of 9600.

" Cisco rollover cable" Not really a rollover. Some junior person might grab that and think they can use it some other place.

If we assume you did use the blue flat cisco cable then I'd think that the tty settings are wrong for terminal. Usually something like 9600 maybe 8 no parity. Defaults could have been changed in cisco too.

@jefro -
The cable that is being used could be more accurately discribed as a Flat Blue DB9 to RJ45 Cisco Console Cable rather than a "rollover" cable.
I would also assume that the TTY settings are wrong. However, in minicom, it shows:
E - Bps/Par/Bits : 9600 8N1

Is there any other location where the TTY settings could be off? Maybe outside of minicom?

What are the settings in windows? 9600 8N1

What's was that other setting? Hardware flow xflow or what?

@jefro -
The only setting I ever adjust in my windows version of putty is the speed or the serial line. Those are currently set to COM3 and 9600. Everything else is set to defult.
As far as minicom, i have serial device set to /dev/ttyUSB0, Bps/Par/Bits set to 9600 8N1, hardware flow control off (set to no), and software flow control off(set to no).

Based off what I see, I know that the cables are good, they work with putty on windows box. I know that the cisco equipment is good and is properly set to 9600 speed. It has to be something within Xubuntu.

Could it be a driver issue? The driver was automatically installed during the OS install process. Are there alternate drivers for me to try?

Are you using the same adapter with windows?

cutecom is a GUI version of minicom except it has a hex mode. Might be of some help to look and see what is actually coming across the bus.

@michaelk
Took your advice and installed cutecom. Very familiar feel. I connected to my 2950 switch and as soon as I powered it up, information came flying accross the screen. I switch to hex output, and then took that output and convert it. Sure enough, the translation converted to ASCII is the unreadable characters I mentioned before.

This is the output:
00000000: 0d 0a 0d 0a 0d 03 09 0a 0d 02 12 0f 0f 11 01 02
00000010: 0a 05 11 15 09 01 02 09 09 0a 0d 0a 09 0a 0f 0f
00000020: 11 15 0a 0a 16 15 09 0d 09 0f 0e 01 0a 12 12 0a
00000030: 02 0a 0a 12 0a 05 05 05 02 09 12 15 14 15 05 0d
00000040: 15 14 1a 15 0a 14 15 15 10 12 15 01 02 09 16 05

So both minicom and cutecom are getting the same bad communication with my cisco devices.

Are you using the same USB adapter with windows?

Yep, except for 0d 0a i.e LF, CR everything else is unprintable text.

@michaelk
Yea, same exact usb adapter. Since it is drastically easier to change your connection settings in cutecom, I even took the liberty to try differnet baud rates, none were successful.

Bump

Stupid question but does the switch output English?