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New Member


I have a cisco catalyst 2924mxl-en, and a number of different non-managed, non-bridging 100baseFX-100baseTX media converters. I unfortunately do not have access to the switch or its configuration, and I was curious whether anybody knew if there was a way to manually set a port to 100mbit/full duplex, since the media converters do not support autonegotiation. Thanks!

New Member

Re: Auto-negotiation

I understand that a Catalyst will set a switch port to half duplex if no FLP responses are received. The manual command is 'duplex full' for the switch port.

New Member

Re: Auto-negotiation

Hi there, when you say you don't have access to the switch, I assume you mean physical access - therefore you can't establish a console connection. If this is the case you could telnet onto the switch and configure the port from there as follows:

set port speed 1/1 100

Where 1/1 is the module/port that the converter is patched into. The 100 represents the fact that you are fixing the speed at 100MB.

The command to set the same port as full duplex would be:

set port duplex 1/1 full

Although autonegotiation is an IEEE standard, it is always best practice to fix a port speed/duplex mode because I've seen no end of problems with differing devices trying to autonegotiate their settings.

Hope this helps,


New Member

Re: Auto-negotiation

For the XL series you will need to set the speed and duplex a little different.


conf t

int fa 0/7 (whatever the port number is)

speed 100 (or 10)

duplex full (or half)


wr mem

This should help you with hardsetting of the switch and just do it on the nic card of that machine as well.



New Member

Re: Auto-negotiation

Hi, I have seen this and dealt with it loads of times... what is at the remote end....

if it is a hub you can plug the hub in, plug the convertor into the hub then connect the fibre to the convertor at the other end and then plug it into the switch... this will give you a half duplex link...

you can use the mode button to fdup if the port is lit it will be full duplex mode. There is a simple method to backdoor the switch and re-setting it up which is on the 2900 website... the other option which I would advise everyone is dont buy convertors they are cheap and nasty...tx-fx bridges are the way to go cheers julian

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