The efficiency of packet switching networks is improved by using a collision avoidance technique rather than collision detection. The subscriber links are connected to a common node. A collision avoidance circuit in each link monitors the node to determine whether it is in a busy or idle status. The first message to arrive places the node in a busy status at which time all other, nontransmitting links are disconnected, thereby avoiding a collision. Later arriving messages are stored in buffers at each subscriber location and are transmitted when the node is again idle. In this manner messages are transmitted on a first-come basis, and can be of arbitrary duration regardless of bit rate.