Straight, and Crossover are two methods of connecting the pins on RJ-45 plugs that attached to a Cat5 Network Cable.
The Rules of Connections for Hub, and or Switch are the same:
NIC to NIC - Crossover Cable.
NIC to Hub - Straight (regular) Cable
NIC to Uplink - Crossover Cable.
Hub (regular) to Hub (regular) - Crossover Cable.
Hub (regular) to Hub Uplink - Straight (regular) Cable.
Hub Uplink to Hub Uplink - Crossover Cable