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.

Abstract: A telephone dialer system consists of a programming unit, and a portable telephone dialer unit for producing a selected sequence of dual tone modulated frequency dialing tones, adapted to be programmed by the programming unit when said portable telephone dialer is releasably electrically coupled to said programming unit. The portable telephone dialer has a case, a reprogrammable memory, a programming interface, a speaker, a battery, a dual tone modulated frequency signal generating integrated circuit chip, and a single bi-state switch operable from the exterior of the case.

Abstract: A pulse receiver for connection in a telephone circuit including two coils connected between a voltage potential and ground further including an external impedance that is alternately connected between the coils. The pulse receiver includes a first impedance connected in series with the first coil and a second impedance equivalent to the first impedance connected in series with the second coil and an input circuit connected across the first impedance for detecting the connection of the external impedance of the telephone circuit. Switching circuitry is provided that is connected to the input circuitry and alters a first output node pair from a normally closed state to an open state and alters a second output pair from a normally open state to a closed state in response to a signal received from the input circuitry indicative of the detection of the external impedance connection.

Abstract: A method and apparatus for automatically determining the amount of a hemoglobin species in a blood sample in relation to the total amount of hemoglobin in a blood sample by simultaneously determining the relative concentrations of the two samples with a spectrophotometer. The spectrophotometer has two channels each of which is associated with one sample. Each channel determines the intensity of light from a light source which is transmitted through its sample and received by a photodetector. Thereafter, the apparatus calculates the relative concentration of the two samples (A.sub.1 /A.sub.2) or optionally the normalized concentration of the samples (A.sub.1 /A.sub.1 +A.sub.2). The apparatus includes automatic self-calibration to compensate for any degradation of the optical system.

Abstract: An electronic switch for use in the tip and ring circuit of a rotary dial telephone pulsing system is disclosed. The electronic switch is a functional replacement for a single pole, double throw electromechanical pulsing relay having normally open and normally closed output terminals, with the state of the output terminals being reversed in response to the connection of an external impedance load to an input sensing node. Normally open and normally closed output nodes are driven by first and second output switching circuits. The operating states of the first and second output switching circuits are reversed in response to a switching signal generated by a binary switch. The binary switch is biased off with no switching signal being produced in the absence of the external impedance load so that one output terminal is normally open and the other output terminal is normally closed.

Abstract: In an optical system including a light source and a photodetector, a circuit and method for compensating for degradation of the optical system which may include deterioration in the intensity of the light source, caused by a variety of factors such as dirt, aging of the light source, etc., or dirt on the photodetector. The intensity of the light from the light source as received by the photodetector is repeatedly measured and an average value determined which accurately indicates the intensity of the light received. Subsequent use of the optical system includes comparison to the most recent average value of light received by the photodetector. Hence the present system eliminates the need for repeated calibration of the optical system by providing the same effect as though the system were being repeatedly and automatically calibrated to account for system degradation.