The original Ethernet protocol was developed by Dr. Robert Metcalfe and his development team at Xerox PARC (Palo Alto Research Center) in Palo Alto, California, in 1972. Ethernet's media access mechanism, Carrier Sense Multiple Access Collision (CSMA/CD), was based on work done by Dr. Norman Abramson at the University of Hawaii on the radio transmission WAN known as the ALOHA system. Metcalfe's experimental Ethernet network, called ALOHA ALTO, supported 100 nodes on 1km length of 50-ohm coaxial cable and operated at a rate of 2.94Mbps. The nodes were connected to the cable with transmitter-receivers (transceiver) and a cable tap. The combination of the cable tap and transceiver is known as an MAU (media access unit).