A switch -- the hub is flooding traffic to all ports, therefore not reducing the collision domain. The switch will give each point to point link its own collision domain.
Setup mode is NOT ROMMON mode. ROMMON mode is ROM Monitor mode, where you change confreg etc. Setup mode is that nice configuration screen the router goes to like when its fresh from the factory where it asks you all sorts of questions and you can do basic configuration quickly.
global command ? I guess you mean global configuration mode.. which is what you're in when you type conf t.
We need a Cisco certified trainer to hang around here more often.