As train speeds increased, the train driver needed to receive information earlier about whether the entry signal would show stop or proceed. This was to allow for the possibility of stopping the train before it passed the home signal. A distant signal was needed to inform the driver what the entry signal showed.

The disc distant signal was placed at a braking distance before the home signal (600-800 metres depending on the maximum permissible speed).

This disc distant signal has been in use in Haparanda.