Method and arrangement for arranging traffic in telecommunications system

A method and arrangement in a telecommunications system comprising a data transmission path (8), the arrangement comprising devices (1, 21, 221 to 22n) and data being transmitted on the data transmission path between the devices in messages (4, 9) cyclically, whereby one or more of the devices (1, 221 to 22n) are arranged, during one or more first turns, respectively, to set the timing of their own cyclic traffic between cyclic traffic detected on the data transmission path; and one or more of the devices (1, 21, 221 to 22n) are arranged, during a second turn, to transmit a message not belonging to the cyclic traffic to the data transmission path on the basis of at least one determined occurrence time slot of the cyclic traffic such that the message does not collide with messages of the cyclic traffic which occur in the determined at least one occurrence time slot.