Abstract: An apparatus for simulating keypad entry of an access code into a security system controller. The apparatus comprises at least one electronic key encoded with a electronic key identifier, at least one electronic key reader adapted to electronically interface with the electronic key to electronically transfer data signals therebetween, a security system controller having memory for storing at least one security code therein and operably connected to a keypad for entering access codes thereon, and simulator circuitry electrically connected to the electronic key reader and operably electrically connected to the security system controller, whereby upon presentation of the electronic key to the electronic key reader, the simulator circuitry interrogates the electronic key then translates the electronic key identifier into an access code.

Abstract: In a particle counting system for sensing and counting particles, a sample fluid is drawn through an orifice from a sample chamber into a substantially enclosed fluid passage at a selected rate sufficient to maintain the pressure in the substantially closed fluid passage at a predetermined pressure level if the orifice and the substantially closed fluid passage are free from leaks and clogs. A sensor detects the actual pressure in the substantially closed fluid passage. The actual pressure is compared to the predetermined pressure level to identify clogs or leaks in the particle counting system. If a clog is identified, an automatic clog removal sequence is inititiated for dislodging or otherwise removing the clog from the particle counting system. The particle counting system is tested to determine if the clog has indeed been removed.