Carrier Sense Multiple Access with Collision Detection (CSMA/CD)

In PLC Communications, devices using CSMA/CD first test the media for the presence of a carrier (Carrier Sense), which indicates that another device is trying to transmit data. If the carrier is absent it then begins its transmission. If the device detects another device is trying to send data (collision detection), it stops transmission and waits a random amount of time before trying again.