<P> The collision recovery procedure can be likened to what happens at a dinner party, where all the guests talk to each other through a common medium (the air). Before speaking, each guest politely waits for the current speaker to finish . If two guests start speaking at the same time, both stop and wait for short, random periods of time (in Ethernet, this time is measured in microseconds). The hope is that by each choosing a random period of time, both guests will not choose the same time to try to speak again, thus avoiding another collision . </P> <P> The jam signal or jamming signal is a signal that carries a 32 - bit binary pattern sent by a data station to inform the other stations of the collision and that they must not transmit . </P> <P> The maximum jam - time is calculated as follows: The maximum allowed diameter of an Ethernet installation is limited to 232 bits . This makes a round - trip - time of 464 bits . As the slot time in Ethernet is 512 bits, the difference between slot time and round - trip - time is 48 bits (6 bytes), which is the maximum "jam - time". </P> <P> This in turn means: A station noting a collision has occurred is sending a 4 to 6 byte long pattern composed of 16 1 - 0 bit combinations . Note: The size of this jam signal is clearly beyond the minimum allowed frame - size of 64 bytes . </P>

Csma/cd is used in a ieee 802.11 because of its half-duplex communication method