A communications system (1) includes a plurality of nodes (2). Each node (2) has receiving means for receiving a signal transmitted by wireless transmitting means; transmitting means for wireless transmission of a signal; and, means for determining if a signal received by said node (2) includes information for another node (2) and causing a signal including said information to be transmitted by said transmitting means to another node (2) if said received signal includes information for another node (2). Each node (2) has one or more substantially unidirectional point-to-point wireless transmission links (3). At least some of the nodes (2) have plural substantially unidirectional point-to-point wireless transmission links (3). Each of said links (3) is to one other node only (2). Each node (2) is arranged such that transmission or reception of a signal at any particular frequency by a node (2) takes place on only one link (3) at a time.