Advanced IP-based emergency telephony solution for Norra Länken

Norra Länken, northern Europe’s largest road tunnel project, has implemented an advanced emergency telephone system based on IP communication from COBS, installed by ISG Nordic AB.

High traffic safety is a requirement in the long rock and concrete tunnels. If an accident should occur, it should be easy to get to safety. ISG Nordic specializes in digital image management and intelligent video and is also responsible for the delivery of cameras and camera systems for both tunnel and surface road networks.

Emergency phones, a necessity

Norra Länken has a total of about 100 escape routes with a maximum distance of 150 meters between them. Each escape route has an emergency room with fire extinguishing equipment and an emergency telephone directly connected to the traffic control center.

A total of 250 emergency telephones have been delivered to the telephone system in Norra Länken. In addition, COBS provided the IP150 – an extremely robust IP phone that can easily be placed outdoors thanks to its weatherproof and vandal-proof casing.

Resistance to moisture, water and dust

Virtually nothing can damage the IP150 – not humidity, water, or even dust. The housing, which is certified to IP65, is made of a robust and strong plastic and is even resistant to acids. The advanced communication system, consisting mainly of redundant central equipment and auxiliary telephones, enables communication between the different areas of the tunnel directly with the Swedish Transport Administration’s switchboard in Trafik Stockholm.

The telephone system is built with redundancy so that failures will not affect the ability to communicate when needed.

Peace of mind for road users

Road users have great peace of mind knowing that in case of emergency there are always direct contact routes with the world above.

The entire system is monitored in real time, and advanced software to test each connected phone is included in the delivery from ISG Nordic. The entire advanced system delivered to the customer is incredibly secure.


The Northern Link in Stockholm extends from Essingeleden at Karlberg in the northwest to the exit to Värtahamnen and Lidingö in the northeast, as seen from the center of Stockholm. The main tunnel is 3.6 km long and was completed for opening in 2014.

(*collected December 2023)