"Normal" twisted pair cable:
	Send messages at one end, receive at other end.
	Voluntary VLAN capability - messages on one VLAN not received by others.
	Also connect to peripherals.
	Promiscuous mode - allows a NIC to receive peripheral messages.

Fibre-optic cable:
	Acts as 16 cables in one - one per Minecraft colour.
	Cannot be split?

Inter-dimensional wiring via nether/end portals

Channels
	128 channels, numbered 1 to 128.
	Modems can listen on any combination of channels.
	Channels 0 and below correspond to computer IDs.
	Messages sent on channel -N will only be received by computer N and computers in promiscuous mode.
	Modems in promiscuous mode will receive all messages on channels 0 and below, but must still be manually added to channels 1-128.