The "transponder holder" is a flush-mounting device for British Standard wall boxes, designed to realize access control systems with a communication support based on KNX bus. It is equipped with one relay (4A @24V AC/DC) and one binary input to be used for connecting external conventional push-button for switch, dimmer and shutter functionalities, or for example for connecting window contact or similar. The output can be programmed as "Linked to access control", receiving in this case switching commands from the device itself (according to card insertion/removal); or being a standard KNX Switch actuator output, able to be controlled by every KNX-standard devices. The white blinking LED placed on the front of the device allow you to monitor device operation and can be also switched ON/OFF in the proper color according to KNX. The transponder reader requires a 12...24 V AC/DC external power supply to ensure its operation even with bus voltage failure.