Audio frequency ripple (AFR) control

The audio frequency ripple control method is the oldest existing method of data transmission on supply lines and may also be termed powerline technology. The function is very easy. One or several AFR amplifiers superimpose an alternating voltage onto the supply voltage. The AFR receivers evaluate the control voltage and use it to switch the relays and thus the lighting. [more]


The function of the European radio ripple control (EFR) is similar to that of the audio frequency ripple control method. With this kind of control system, data is not transmitted through the electricity network but by means of long-wave radio.

By definition, long waves are waves in the frequency range 30 to 300 kHz. In the installation, the EFR receivers are located either in the sub-distribution or in each lighting point. [more]


The lighting cable is switched from the service centre or by means of a brightness sensor. In order to keep the extent of the wiring low in this case, the cable does not simply end at the last luminaire but is routed on to the next sub-distribution. From there, the lighting cable again controls a power contactor (blue circle), so that the lighting cable leading onward and newly supplied is then switched. [more]

Control line

When new long-term plans were made for the infrastructure of a municipality or city and control of the lighting system was included in this context , one or several control cables were installed to this end. This concept has been viable for a very long time because often the plan only included switching or reduced-power operation. This absolutely enabled economical control of 1-/2-lamp luminaires, alternatively also of reduced-power luminaires with magnetic ballasts. [more]

Astronomical clock

Control by means of astronomical clocks is frequently used. The clocks installed in sub-distributions control the lighting system. In particular, the possibility of synchronisation using the DCF 77 signal - the atomic clock time from Brunswick - provides the time of the year as a source of information in addition to the time of day. In this way, lighting control can very well be adjusted based on the time of the year and the knowledge of longitude and latitude. [more]

Brightness sensor

In smaller, rambling municipalities, lighting systems controlled individually by means of brightness sensors are also used. Brightness sensors that switch the lighting cable are installed in the sub-distributions. A major advantage of such systems is that the actual dependence of the light values measured on site is used to control the lighting. This means, on the one hand, very good control but, on the other, decentralisation may result in different switching points. [more]