Noiseless solid-state relay, also energy saving lamps ESL and LED lamps. Switch-off early warning and pushbutton permanent light switchable. Standby loss 0.4 watt only. With ESL optimisation and multifunction. Zero passage switching to protect lamps. This prolongs in particular the lifetime of energy saving lamps. Additionally 8 to 230V UC electrically isolated universal control voltage. 3-wire and 4-wire circuits, resettable, with attic lighting if 4-wire circuit. Automatic detection of the method of connection. Glow lamp current up to 50mA, ­dependent on the ignition voltage of the glow lamps. Precise variable time range from 1 to 30 minutes, settable by minute scale. Permanent light switch with the big rotary switch. If the function TLZ is set, the lighting is switched on again after a power failure provided the set time has not yet elapsed. With double connections for pushbutton and lamp in order to connect either above or below or only below. If switch-off early warning function is switched on the light starts flickering approx. 30 seconds before time-out and is repeated three times at decreasing time intervals. If pushbutton permanent light is switched on permanent light can be switched on by pressing pushbutton longer than 1 second. This is switched off automatically after 60 minutes or by pressing pushbutton longer than 2 seconds. If both switch-off early warning function and permanent light pushbutton are switched on, the switch-off early warning function is activated before the permanent light switches off.