Communication of the participants in the traffic with assistance services or providing information is realized through the telephone call system – TPS. The TPS device is a SOS phone that is connected via an Ethernet network with COKP and has two-way communication. All SOS phones are planned locally and COKP operators have a detailed overview of where the call is being made, and they can also call each device. The TPS device is located inside the SOS niche in tunnels, in front of and behind each tunnel, and every 2 km along the entire highway.