10Base-5 is the classic version of a CSMA/CD bus system with baseband transmission and corresponds to Ethernet DIX V.2, standardized by IEEE 802.3. 10Base-5 corresponds to the original Ethernet. The transmission medium used in 10Base-5 was a thick, rather bulky coaxial cable, the Yellow Cable. Therefore, this Ethernet variant is also referred to as Thickwire Ethernet.
The 802.3 working group specified various boundary conditions for the 10Base-5 Ethernet interface. For example, a LAN segment, including all transceiver cables, must not be longer than 500 m. In addition to the length limitation, the number of connectable stations is also limited to a maximum of 100 transceivers (MAU), with a minimum distance of 2.5 m between the transceiver connections. With a minimum signal propagation speed of 0.77c, this results in a propagation delay of no more than 2,165 ns. An AUI cable may not be longer than 50 m; with a minimum signal running speed of 0.65c, this results in a maximum propagation delay of 257 ns.segments; of the LAN segments, however, only three segments may be coaxial segments. The other LAN segments result from the max. 1,000 m long point-to-point connections between the remote repeaters. Thus, the maximum distance between two stations is 2,500 m. signaling. As a result, 10Base-5 and V.2 stations coexist on the same coaxial cable, but cannot send messages to each other.