Suitable for connection to external systems such as KNX via corresponding binary inputs. Suitable for connection to external systems such as Busch-free@home via corresponding binary inputs or extension inputs of the wireless sensor/actuator combinations (eg 6211/1.1-WL). Relay contact: potential-free changeover contact 230 V~ max. 5A Cable connection: up to 2 x 2 x 1.5 mm² With built-in radio module.