ET200M backplane bus cover

Dear all.
I want to use ET200M with active backpane bus. I read in ET200M manual, it have backplane bus cover, but I dont know, what is backplane bus cover, When I use it.
Thanks.

A guess:
"backplane bus cover" = A little plastic thingy that covers the connector when not used.

If memory serves me correctly.. The ET200M is a 'rack' with an IM153 and slots for up to 8 I/O modules, the same modules used with S7300's, so I think Jespers guess is spot on, if you only fit 4 modules in the rack then you will need 4 bus covers, to cover up the other 4 slots..

Now that makes sense

Paul

Or a piece of all-purpose calibrated electrical tape?