so you don't have to break the multi-block when u building above it and u don't wanna lose any items in the process

16k rf internal buffer

Just cut the power of the rock crusher. When it does not have any power, it will no longer crush items.

At current you can use buildcraft gates to pause the work.

that works. edit: no it doesn't ... I did not know about this "gates.action.pause" function.

it still destroys items that cant go in the inventory and still accepts items it just doesn't process them.

With the buffer removed, you can now just cut off the cable as originally suggested.