The original IEEE 10 Mbps Ethernet standard which used a bus topology comprising a thick coaxial cable. Network nodes attached via an "AUI interface" to transceivers that tapped into the bus. Also called "thick Ethernet," "ThickWire" and "ThickNet," 10Base5 had a distance limit of 1,640 feet without repeaters. See 10Base2
10Base5 "Thick" Ethernet
The first Ethernet used a bus topology, which was a common coaxial cable that ran by every node. Transceivers, which connected to the nodes via 15-pin AUI sockets, typically used a "vampire" tap to "bite" into the coax bus.