We have a few places where we need more than 8 switches in a building. Because the primary stack is acting as the router for the building we need to connect a second stack to the primary using an L2 link.
In one of our cases this stack is in the same closet and close enough that a DAC (stacking cable) can reach!
The DAC cable runs at 10G and comes ready to plug into the SFP ports on each side, a perfoect fit!
This is a great cost effective solution to get a 10G L2 link between S3500/2500 stacks.