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Cisco 3850 Console Port - USB / RJ45 .....

ddavies016
Level 1
Level 1

Hey up folks!  I am currently having a play round with a reasonably new switch:-

Cisco WS-C3850-24P - with power inline etc...  currently running SW Version - 03.02.02.SE

I appreciate the documentation details about use of EITHER a USB or an RJ45 console, and that both output data regardless of which is the active console.

My problem though is that I would much prefer to work through the RJ45 for the time being, and despite entering an expilict "media-type" command under the console line - it refuses to let me communicate to the switch via RJ45???

Has anyone else out there come across this issue?   I through I would throw it out to the Cisco community first before going through the arduous task of raising a Cisco TAC Case.

Many thanks in advance for anyone who might be able to help out?

1 Accepted Solution

Accepted Solutions

InayathUlla Sharieff
Cisco Employee
Cisco Employee

Console Setup

The Cisco Catalyst 3850 Switch (similar to the Cisco Catalyst 3750-X Switch) has two console ports: a USB mini console port in the front and an RJ45 console port in the rear. You can use either port (but not both) for input. However, both ports always display the switch output.

The default console port speed setting is 9600 baud, 8 data bits, no parity, 1 stop bit, and no flow control.

Using the USB Console Port

Figure 1. USB Console Port

The USB console port is the default management port and is supported in both install and boot loader modes.

Before using the USB port, download the required driver to your PC from Cisco.com:http://software.cisco.com/download/release.html?mdfid=282979369&softwareid=282855122&release=3.1.

The USB console port has a configurable inactivity timer that automatically disables the port after a specified period from 1 to 240 minutes. Use this command to configure the inactivity timeout interval:

Using the RJ45 Port

Figure 2. RJ45 Console Port

To use the RJ45 port, you must configure precedence for it by using these commands:

Configuring precedence for the RJ45 port enables it for input and disables input on the USB console port. However, switch output is always displayed on both ports.

HTH

Regards

Inayath

View solution in original post

8 Replies 8

InayathUlla Sharieff
Cisco Employee
Cisco Employee

Console Setup

The Cisco Catalyst 3850 Switch (similar to the Cisco Catalyst 3750-X Switch) has two console ports: a USB mini console port in the front and an RJ45 console port in the rear. You can use either port (but not both) for input. However, both ports always display the switch output.

The default console port speed setting is 9600 baud, 8 data bits, no parity, 1 stop bit, and no flow control.

Using the USB Console Port

Figure 1. USB Console Port

The USB console port is the default management port and is supported in both install and boot loader modes.

Before using the USB port, download the required driver to your PC from Cisco.com:http://software.cisco.com/download/release.html?mdfid=282979369&softwareid=282855122&release=3.1.

The USB console port has a configurable inactivity timer that automatically disables the port after a specified period from 1 to 240 minutes. Use this command to configure the inactivity timeout interval:

Using the RJ45 Port

Figure 2. RJ45 Console Port

To use the RJ45 port, you must configure precedence for it by using these commands:

Configuring precedence for the RJ45 port enables it for input and disables input on the USB console port. However, switch output is always displayed on both ports.

HTH

Regards

Inayath

Yep I got that from it's original source, what I am describing here though is on my switch, it ain't working!

Let me allaborate a little -

I have applied the following command:-

!

line con 0

media-type rj45 switch 1

!

Which "should" enable the RJ45 for input - but it is not working, I have tried several different cables and even different machines with different software for accessing the console, and whilst in all cases I can see the output I cannot interact with it?

There is nothing plugged into the USB port during this either.

I'll add also that this is a single un-stacked switch.

can you try this:

#config t

Switch(config)# line cosole 0
Switch(config-line)#media-type rj45
Switch(config)# end

RJ-45 Console Port

The RJ-45 console port is on the rear panel of the switch.

Step 1 Connect the RJ-45-to-DB-9 adapter cable to the 9-pin serial port on the PC. Connect the other end of the cable to the switch console port.

Step 2 Start the terminal emulation program on the PC or the terminal. The program, frequently a PC application, such as HyperTerminal or ProcommPlus, makes communication between the switch and your PC or terminal possible.

Step 3 Configure the baud rate and character format of the PC or terminal to match the console port characteristics:

9600 baud

8 data bits

1 stop bit

No parity

None (flow control)

Also check the LED status:

RJ-45 Console Port LED

Table 1-14     RJ-45 Console Port LED

Color

RJ-45 Console Port Status

Off

RJ-45 console is disabled. USB console is active.

Green

RJ-45 console is enabled. USB console is disabled.



HTH
Regards
Inayath

Thanks for the tips - to put things in context, I have been working with Cisco Routers and Switches for more than 20 years, so I am confortable with the troubleshooting steps to follow... 

I can confirm I have followed all of the recomendations you have posted and that despite the green light being visible, and the line of config being present - the console still doesn't behave as I would expect it to. 

I am feeling like this may be a faulty box/port maybe?  but the fact it still sends out information is what led me to look to the wider community in case there was something obvious I was missing. 

From your updates it would seem I am not missing anything and that I really need to be raising this as a TAC with Cisco?

Sorry Dave for frustating you.

It looks to me there is issue with the port on this box.

I hope  the USB port responding to the console ?

Yes good idea is to raise the TAC and get the box replaced there is not much troubleshooting can be done on the console port as the same console cable is working on other box.

Regards

Inayath

Hey ddavies,

I dont know if you are still having this issue.  Both, the usb and the rj45 would display output but only the usb would accept input. (of course only one cable plugged in at a time). 

The solution was i forgot to disable flow control on SecureCRT, just make sure everything is unchecked under flow control.

many thanks for all the replies people, it turns out in our case we really did have a faulty RJ45 port.  So after an RMA we are back on track

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