A cam system comprising a plurality of CAM devices connected in a serial cascade arrangement, the CAMS in the cascade being connected to an adjacent CAM by a respective forwarding bus, with at most a first CAM in the cascade being connected to a receive data signals from a host controller and at most a last CAM devices being coupled to forward results back to the host controller; and a send signal generation means for supplying a SEND signal to the last CAM; the SEND signal for co-ordinating transfer of the search result from the last CAM to the host controller, the serial cascade arrangement minimising the number of CAMs being connected to a common forwarding bus.