As we seem to have run into several semantic confusions, here's a glossary of some terms that have been misunderstood or created during our discussion. Please add any such terms you may have found.

Device

a piece of hardware connected to a Remote Node that has its own port number

Host PC

the computer used to control the complete robot (when not autonomous)

Main Board

the board on the robot which contains the CPU. This board communicates with the host and controls all the remote nodes

Module

either a RHexLib module or a Remote Node.

Node

see Remote Node

PC

see Host PC

Pipe

a logical sub-channel in the USB bus. Pipes can have varying characteristics (e.g. isochronous vs. bulk) and bandwidth allocations.

Port

a number used to identify a communication end-point for a device in the robot.

Remote Node

a hardware and software sub-system in the robot that has its own processing capability. Much of the discussion has focused on the communication medium and protocols that connect the nodes to the main board. In some of the earlier parts of the text (before AlRizzi coined the term "remote node") the term Module was used.