As early as 1973, SJ began designing a fully automated radio system with portable devices for all railway lines throughout Sweden. The system was designed for a maximum of 2000 portable radio units. Since such a device is what we now refer to as a mobile phone, it can be said that this was an early mobile phone network, probably the first in the world.

Operations radio is used for communication between management and maintenance personnel along the railways and connecting roads. Communication can occur between radio-to-radio, radio-to-telephone, and telephone-to-radio.

Traffic radio is primarily used for communication between train drivers and traffic control. The traffic radio device is an operations radio device built into a console in the locomotive. It utilizes the same radio network as the operations radio. The introduction of traffic radio in 1979-1980 led to heavy network congestion, significantly reducing throughput, especially during daytime. Over time, NMT devices were introduced as supplements.

The operations radio network has now been replaced by a modern digital GSM system.