Fiber problem - special commands needed on switch???

[lsmart]

I have single mode fiber connected between a 3560 and the 4506.

I am using the ZX (long distance - big bucks) modules.

I installed a -10db attenuator between the two pieces of equipment

My issue

When I do a no shut on the port, the green light comes on the gbic of the 3560. The it goes off and the port goes into err-disable

Is there a special command you need when connecting SM fiber?

[joveroc]

I had a similar issue last week between all my 3550's and our core 6513 switch after a sever power failure. Like you the light on the 3550 would go green for a few seconds and then err-disable. When I debugged the 3550 I found that the interface was having a 'linkstate-flapping' issue that caused it to err-disable itself. I ended up having to turn off speed negotiation at both ends of the link and manually shutdown and enable the port on the 3550 to clear the err-disable state. I then configured the 3550 to automatically retry the link every minute if it ever goes to the err-disable state again. I guess the first step to solve your issue would be to monitor the terminal on the 3560 and see exactly what error it is returning when it goes to err-disable and move from there.