(Carrier Sense Multiple Access/Collision Avoidance) A transmission technology that attempts to avoid collisions rather than detect them as in CSMA/CD. Used in wireless Ethernet (802.11) and Apple's LocalTalk, when a device needs to transmit, it listens to the network (senses the carrier) and waits for it to be free.

In 802.11, it then waits a random period of time and transmits. If the receiver gets the frame intact, it sends back an ACK to the sender.

In a LocalTalk network, when the network is free, the sending device broadcasts a tiny control packet indicating that it wants to transmit. All other stations wait until the data packet is transmitted. See 802.11 and CSMA/CD.