console port locks

[KeithN123]

I have a 2811 with 16 serial lines for reverse telnet to my labs.   I have 10 devices consisting of 4 switches and 6 routers.  I can connect all devices except one. I have tried changing the octal cable, re-configuring the 2811 and even replaced the end router. The connection comes up initially but after a few lines it locks. I thought it may be a flow control problem but all lines are set to none.

Has anyone experienced this problem before and if so how was it resolved ? I have attached the configuration of the terminal server.

many thanks

Keith

Message was edited by: KeithN123

[Phillip Remaker · Accepted solution]

Does the problem track the port, or the device?

For example, if you swap the device on the failing port with a working one, do you get the same behavior on that port, or does the problem follow the device?

If the device, what is the device that is causing the problem?  How long is the physical wire to that device?

[KeithN123]

hi Phillip

Many thanks for taking the time to look at this problem.  Fortunately, our problem has now been resolved and I can mark this query as fixed - please accept my apologies for not having done this sooner.

It appears that someone within our network team had changed the console configuration on every device - the only place I didn't look - why change something that is working, right ?

again many thanks for taking time to look at this.

regards

Keith

[Phillip Remaker]

Unfortunately, Cisco does not make it easy to tell the console speed.  The quirk is a legacy of the product history.

Back in the stone age, when dinosaurs roamed the earth and 56kbps was a fast WAN connection,  there was a physical set of jumpers on the main CPU board (the CSC/[1234]) of the AGS/MGS/CGS series to set the console port speed (and other things).  This jumper block was called the 'configuration register."  The earliest Cisco boxes did NOT have any NVRAM, and this was the only means to initially configure the device.

Over time, this physical jumper block was deprecated (first by the IGS series) and replaced by a two-octet word stored in NVRAM to represent this formerly physical jumper block.  This NVRAM value is set using the "config-register" command..

Interpreting the console speed is explained here:

http://www.cisco.com/en/US/products/hw/routers/ps133/products_tech_note09186a008022493f.shtml

The console port had a maximum of 9600bps in the older Cisco product lines.  Higher speeds (and additional bits inb the config register) were added in more modern products.