Does coaxial cable transfer data both ways although it has 1 wire in it? How coaxial cable is different from Ethernet cables? And why does Ethernet cables have two wires for transmit and two wires for receive?
Thank you in advance.
Network Engineering Stack Exchange is a question and answer site for network engineers. It only takes a minute to sign up.Sign up to join this community
Ethernet over coax is half-duplex. This is one of the main reasons for collision detection: figuring out a way such that multiple stations can transmit without stepping on each other. With modern switching (...and dedicated media for transmit and receive) the need for sensing collisions and managing the timing of retransmission is eliminated.
As Zac67 points out, some versions of ethernet, e.g. 10BASE-2 and 10BASE-5, actually used coax. Ethernet uses CSMA/CD (Carrier Sense Multiple Access with Collision Detection). Only one device on the coax can transmit at a time. A device must listen to the carrier to see if another device is sending, but it does take time for a signal to fill the medium, so it can happen that two devices start sending at the same time. If two devices try to transmit at the same time, you get a collision, and both devices back off for a random time so that they don't both start sending at the same time.
This is really a rather large subject, and there is much literature on it if you search.
Ethernet cables have two wires for transmit and two wires for receive?
Because ethernet uses differential signaling to transmit the signals, and that increases the resilience against external electromagnetic interference: