I want to discuss this a bit, along with a simplified How-to. The biggest and most prevalent networking medium used today is Ethernet. Ethernet's success was due largely to its incredible flexibility as a multiprotocol medium- which means it can route many different network packet types at the same time. Very simply put, Ethernet is a specification to packetize, or to create equal chunks of data with CRC info to a digital stream of information. Economies of scale made Ethernet cheaper and cheaper, enabling the networking renaissance we are enjoying today.
Ethernet is remarkably simple to implement.
Coaxial wire functions without a hub, and utilizes its own internal resistance as a guide. At the end of the coaxial chain, a terminator is placed to connect the two leads of the wire together at a higher resistance and return the packet along the receive lead, completing the cycle. The receiving computer will respond if the packet passing through its NIC is addressed to it, and the whole thing starts again. The problem with coax cable is that its expensive and its only functional for a limited length before the resistance becomes too great, much like SCSI cabling. Twisted pair is much cheaper to cable, but requires some arbitration in the signaling, since the wires don't have the type of internal resistance necessary to simply terminate .