Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
New Member

Unreadable CLI Text - Catalyst 3650G

Hi all,

I'm having a really frustrating problem with one of our Catalyst 3650G switches.

When connecting via serial the text appears unreadable. Most of the internet searches I've completed tell me that the baud rate is incorrect on the management software (in this case, Putty) so change it back to 9600.

However, I've been using this setting all along and if I remove the console cable from the switch and plug into the PIX and open Putty using the same serial settings, it works absolutely fine. I've been through all of the baud rates with no joy.

Here's the settings I've been using in putty:

Baud rate: 9600

Data bits: 8

Stop bits: 1

Parity: None

Flow Control: None

I've even played around with the other settings other than baud rate but all with no joy. I've even gone to measures such as using a different laptop, different cable and different software - TeraTerm Pro and HyperTerminal. All of which haven't helped.

Unfortunately the device was reset to factory settings in the web console before connecting to the serial console so now I am unable to connect to a web GUI or telnet to do anything as both are disabled.

Here's an example of the serial output I've copied from the CLI:

J%(Plecse answer?'yes' or?'no'.tial configuzation dialog? [yes/no??

Woumd you |ike t66?d7[6d?[[?m???lm?7n??ion!dialow? [yes/no]:

- Please answer 7yes' or$'no?.

Would you lkke |o mnuer the initial ?onviguration lialog? [yes/no]:

oul?(you nike to enter tle`initial co?figuration fi?}ow? [yes/no]:

Please can anyone suggest what else it may be?

Many ahanks in advance!

1 ACCEPTED SOLUTION

Accepted Solutions

Re: Unreadable CLI Text - Catalyst 3650G

The frustrating thing is that the text is almost correct, so that implies it is probably not a baud rate problem. If it was set to the wrong baud rate, you would not recognise any of the text at all.

Have you tried with a PC rather than a laptop? I remeber some discussion about the serial interfaces on laptops being out of spec because of power supply limitations. The V.24 interface voltage levels are both plus and minus. A "real" PC has both +12V and -12V available from the PSU. A laptop has only the +12V (or maybe only the +5V, I don't know.) The laptop therefore drives +5V and 0V, and hopes the other end has thresholds that detect those levels.

Also, check the common ground reference connection on the cable.

Kevin Dorrell

Luxembourg

6 REPLIES
Hall of Fame Super Silver

Re: Unreadable CLI Text - Catalyst 3650G

Daniel

I do not have much experience with this particular model device. But the symptoms are probably common across devices. The symptoms are very much like the symptoms that the speed of the console port on the switch have been changed. My suggestion is to use a different PC or laptop to investigate this problem. If it were me I would use TeraTerm or Hyperterm but that is mostly that I am more familiar with them than I am with Putty.

I would start with the terminal software set to speed 1200 and try to connect. work your way up the various speeds and I would stop and start the terminal software every time that I changed the speed.

HTH

Rick

New Member

Re: Unreadable CLI Text - Catalyst 3650G

Hi Rick,

Many thanks for your suggestion but as stated above, I've already tried a different laptop/cable and both HyperTerminal and TeraTerm Pro. All of which to no avail. I've also been through all baud settings from both laptops and using both Putty and HyperTerminal.

This switch was only bought in July/August 2006 and hasn't been used since about October 2006.

Regards,

Daniel

New Member

Re: Unreadable CLI Text - Catalyst 3650G

Try booting the switch with the "mode" button held in, this should bring you to the switch: prompt at the standard 9600.

use the "set" command to see what env. BAUD is set to and hopefully reassure you that the switch hasn't got a hardware problem(or has it). Now do "flash_init" followed by "set" again to see if you can make out if BAUD is still the same or different since the stored values off the flash were read.

I'm not sure of the significance, but for those characters in your paste that happen to have been transposed to a printable char rather than ?, there only ever seems to be 1 bit incorrect in each byte.

e.g.

f only differs from v at bit4

r -> z bit3

a -> c bit1

t -> u bit0

m -> e bit3

hope I've at least opened a couple of avenues to explore ...

Tim

Re: Unreadable CLI Text - Catalyst 3650G

The frustrating thing is that the text is almost correct, so that implies it is probably not a baud rate problem. If it was set to the wrong baud rate, you would not recognise any of the text at all.

Have you tried with a PC rather than a laptop? I remeber some discussion about the serial interfaces on laptops being out of spec because of power supply limitations. The V.24 interface voltage levels are both plus and minus. A "real" PC has both +12V and -12V available from the PSU. A laptop has only the +12V (or maybe only the +5V, I don't know.) The laptop therefore drives +5V and 0V, and hopes the other end has thresholds that detect those levels.

Also, check the common ground reference connection on the cable.

Kevin Dorrell

Luxembourg

New Member

Re: Unreadable CLI Text - Catalyst 3650G

Many thanks for your advice Kevin!

It turns out that although I tried using different laptops, it was indeed caused by power supply limitations. Once I plugged into a normal desktop machine, it worked perfectly!

Thanks again!

Re: Unreadable CLI Text - Catalyst 3650G

That does not look like speed TBH. Could you add a sh ver and a sh run of line con 0?

1382
Views
0
Helpful
6
Replies
CreatePlease to create content