Abstract: A card reader device which consumes almost no power until a user's access card is presented includes a power source module, a wireless tag reader, a switch module, and a sensor. The switch module can electrically connect and disconnect to the power source module and the wireless tag reader. The sensor can detect a change in a magnetic field caused by proximity of the access card. When the card reader device is not in use, the switch module is turned off, and the power source module does not provide power to the wireless tag reader. When the change in the magnetic field is detected by the sensor, a signal from the sensor turns on the switch module, and the power source module provides power to the wireless tag reader. A related access system employing the card reader device is also disclosed.

Abstract: The present invention relates to a filter device, the filter device includes a housing provided with a through-hole; and a filter structure includes a signal line; a wave filter connected to the signal line, the size of the periphery of the wave filter smaller than the diameter of the through-hole; a connecter connected to one end of the signal line and connected electrically with the wave filter; wherein the filter structure is arranged from the outside of the housing through the through-hole correspondingly, so that the signal line and the wave filter are arranged at the inside of the housing and the connecter is fixed at the through-hole. Hence, the filter structure is locked and fixed optionally from the outside or from the inside of the housing to increase the convenience of the whole assembly.

Abstract: The present invention relates to a filter device, the filter device includes a housing provided with a through-hole; and a filter structure includes a signal line; a wave filter connected to the signal line, the size of the periphery of the wave filter smaller than the diameter of the through-hole; a connecter connected to one end of the signal line and connected electrically with the wave filter; wherein the filter structure is arranged from the outside of the housing through the through-hole correspondingly, so that the signal line and the wave filter are arranged at the inside of the housing and the connecter is fixed at the through-hole. Hence, the filter structure is locked and fixed optionally from the outside or from the inside of the housing to increase the convenience of the whole assembly.