A signal that carries a bit pattern sent by a data station to inform the other stations that they must not transmit. Note 1: In carrier-sense multiple access with collision detection (CSMA/CD) networks, the jam signal indicates that a collision has occurred. Note 2: In carrier-sense multiple access with collision avoidance (CSMA/CA) networks, the jam signal indicates that the sending station intends to transmit. Note 3: "Jam signal" should not be confused with "electronic jamming. "