2-stage ventilation relay, 1+1 normally open contact potential-free 16A/250V AC, with DX technology. Bidirectional. Stand-by loss only 0.1 watt. Connection to the Eltako RS485 bus. Cross-wiring bus and power supply with jumper. To do this, simply connect the N conductor to the terminals (N1) and L to 1(L) and/or N to (N2) and L to 3(L). This results in an additional standby loss of only 0.1 watt. If the supply voltage fails, the switching state is retained. With recurring supply voltage is switched off in a defined way. This ventilation actuator evaluates the information of up to 23 passive sensors, such as radio buttons, window-door contacts, window-grip sensor FFG7B-rw or radio transmission modules. Active sensors for CO2, humidity or temperature are also evaluated. Several active sensors can be linked with the PC tool PCT14. If the two contacts are connected in parallel, the 2-stage actuator for 2 fan speeds becomes an actuator for a fan. The middle rotary switch is required in the