Abstract: A device and a method used during installation of a security system that allows the security system control panel to learn the IDs of the wireless transmitters in the security system without receiving an RF transmission from the wireless transmitter. The installation device comprises a power supply means, a first and second interface means, monitoring means for monitoring the current drawn from the power supply means, and processing means for producing a digital signal based on the current monitored. The first interface means connects the power supply means of the installation device to the battery terminal of the transmitter, and the second interface means connects the output of the installation device to the control panel. The monitoring means, comprising a resistor and a comparator, monitors the current drawn from the power supply means, wherein the current drawn corresponds to the data transmitted by transmitter.

Abstract: A security system comprising a control panel and a plurality of individually-addressable security system modules connected to the control panel on a loop data bus. Each of the security system modules has a reference generating means for generating a variable reference voltage signal, which is controlled by control data received from the control panel. Each module also has means for selecting a loop input signal for analysis from a plurality of available loop input signals, and comparing means for comparing the selected loop input signal to the reference voltage signal. The comparing means generates an output signal when the selected loop input signal exceeds the reference voltage signal. The modules also have means for indicating to the control panel via the loop data bus the state of the reference generating means when the comparing means generates an output signal, whereby the control panel can determine the value of the selected loop input signal.

Abstract: Provided is a system and method for detecting marginal data transmissions from any of a number of security devices in a security system including a control unit in communication with the security devices over a serial data communications loop. First, the control unit receives a data transmission from a security device, wherein the data transmission includes a number of bit intervals in which a logic 1 level is assumed by the control unit unless a logic 0 level is detected by the control unit. The control unit samples the data transmission at a first predetermined time during the bit interval to obtain a first sample value, and then it samples the data transmission at a second predetermined time during the bit interval to obtain a second sample value (the second predetermined time being later than the first predetermined time). If the first sample value is a logic 1 and the second sample value is a logic 0, this indicates that the data transmission from the security device is marginally recoverable.

Abstract: In a security system that has a large number of individually-addressable modules interconnected on a data bus to a control panel, a method of concurrently supervising the modules by first configuring each module with a unique zone number including a group number and a module number. During operation, the control panel initiates a group supervision poll sequence for each group number by transmitting a group poll command including a group number data field populated by the group number currently being polled. If a module is part of the group being polled, then it sets a discrete bit appended to a group poll response message that logically corresponds to the module number for that module. The control panel then determines if any bit in the group poll response message has not been set, and then issues a unit poll sequence addressed to a module that corresponds to any such bit not determined to have been set in the group poll response message.

Abstract: Disclosed are three major aspects relating to wireless transmission of encrypted data messages in a security system wherein the receiver stores locally an encryption key utilized by the transmitting device to encrypt the data message and the receiver uses the encryption key to decrypt an encrypted data message, and wherein a sequence number generator is used to synchronously track the message sequence at both the transmitter and receiver. A first major aspect involves encrypted device registration (learning) methods that are user-friendly and immune from detection by technically skilled intruders with special RF equipment, and periodic user-friendly changing of the encryption key per encrypted transmitting device in the system. A second major aspect involves encrypted device de-registration (unlearning, or deletion) that is likewise user friendly.

Abstract: A method of arming a security system comprising one or more send-only RF sensor. The method comprises the steps of receiving a request to arm the system from a keypad, determining if a faulted status exists in the receiver/controller, if a faulted status does exist, then changing the faulted status to a restored status, and arming the security system when there are no faulted statuses in the receiver/controller.

Abstract: Disclosed are three major aspects relating to wireless transmission of encrypted data messages in a security system wherein the receiver stores locally an encryption key utilized by the transmitting device to encrypt the data message and the receiver uses the encryption key to decrypt an encrypted data message, and wherein a sequence number generator is used to synchronously track the message sequence at both the transmitter and receiver. A first major aspect involves encrypted device registration (learning) methods that are user-friendly and immune from detection by technically skilled intruders with special RF equipment, and periodic user-friendly changing of the encryption key per encrypted transmitting device in the system. A second major aspect involves encrypted device de-registration (unlearning, or deletion) that is likewise user friendly.

Abstract: A self-testing data communications system suitable for use with an alarm system, the communications system being capable of modifying an operational parameter such as the input signal sensitivity of a receiver located at a monitoring station during receipt of a supervision signal from a remote alarm device, in order to ensure that a non-supervision alarm signal will be properly received when the operational parameter is again returned to its normal state.

Abstract: A plurality of serially addressable devices connected to transmit data to or from a central controller via a two-wire polling loop has a global poll capability. The transmissions of data are via a tri-level line signal to provide both power and data transmission on a two-wire line. Global polling is initiated by a preamble recognized by each device in the loop. The preamble is followed by a single bit sequence to allow the devices to signal the central controller that one or more devices will respond to the global poll. If one or more devices will respond to the global poll, a series of bit sequences is generated by the central controller equal to the number of bits that will be transmitted by the serially addressable device to transmit its address and status.

Abstract: A glass breakage detector utilizes a single microphone or piezoelectric element as a transducer to detect both the structurally-transmitted vibrations and airborne sounds indicative of breaking glass. The structurally transmitted component and airborne component are combined in accordance with a time-dependent function to provide an indication of breaking glass which has a low false alarm rate.

Abstract: Methods and apparatus for evaluating installation of components of a wireless type of alarm system or the like that includes a plurality of satellite stations, each of which includes a sensor and associated transmitter circuitry responsive to the sensor for transmitting an alarm signal and a central station for receiving the alarm signal and operating an output device in response to the received signal. The system includes alarm signal processing circuitry that has a first (normal) mode for processing the received signal and second (installation) mode in which a characteristic of the received alarm signal is impaired so that a received signal of greater quality than in normal mode is required to operate the output device.

Abstract: The invention provides apparatus for evaluating installation of components of a wireless type of alarm system or the like that includes a plurality of satellite stations, each of which includes a sensor and associated transmitter circuitry responsive to the sensor for transmitting an alarm signal at radio frequency, and a central station for receiving the alarm signal and operating an output device in response to the received signal. The installation evaluating apparatus includes signal strength sensing circuitry responsive to the strength of the alarm signal received at the central station, and an RF transmitter responsive to the sensed signal strength for transmitting an indicator signal to a receiver at the installation location of the satellite transmitter device being evaluated, the nature of the indicator signal received at the transmitter site providing an indication of the quality of the RF transmission path between the transmitter and the central receiver.

Abstract: In a keyboard having two depressable key switches which receive pulses of a first given width and transmit in response thereto pulses whose width is a function of the mechanical travel of the key switch, the travel of the key switches is detected by feeding a pulse of a first given width alternately to the key switches, sensing for the width of pulses transmitted by the key switches in response to receipt of the pulses of first given width. When the width of a pulse transmitted by one of the key switches in response to the receipt of one of the pulses of the first given width exceeds a second given width which is less than the first given width, there is fed a series of the pulses of first given width only to such one key switch and none of the pulses to the other of the key switches.

Abstract: In a magnetic recording system utilizing a non-return-to-zero format the reproduced recording is fed to positive and negative threshold detectors having no need for electrical hysteresis as well as, via differentiator means, to a zero-crossing detector. The signal from the positive threshold detector and one polarity of the signal from the zero-crossing detector are used to trigger a latch means to a first state to emit a signal having a first level, and the signal from the negative threshold detector and the other polarity of the signal from the zero-crossing detector are used to trigger the latch means to a second state whereby the signal emitted by the latch means is switched to a second level.

Abstract: In a display device having a record medium which is parallel-line raster scanned by a beam which is intensity modulated to form matrices of dots representing symbols, apparatus is provided to generate composite symbols such as characters with diacritical marks. The apparatus includes a source of groups of coded combinations of bits representing symbols with each group having a first part representing the character and a second part the diacritical mark. A first addressable memory stores the binary signals representing the dots of the character while a second addressable memory stores the binary signals representing the dots of the diacritical marks. Thus, each symbol group addresses two memories which then feed these binary signals to the beam which is intensity modulated to form a matrix of dots on the record medium. In addition provision is made to vertically displace the characters to perform subscripting and superscripting.

Abstract: In a cathode ray tube (CRT) display system using a horizontal line raster scan, the vertical sync signals are derived from the power line alternating current while the vertical blanking signals to blank the vertical retraces between rasters are timed to occur over an interval which starts before a vertical sync signal and ends a period of time after the vertical sync signal which is no less than the minimum time required for a vertical retrace.

Abstract: A variable mode counter has a control means switchable between first and second states, a source of periodically occurring step signals, a counter means, and incrementing means under the control of the control means for incrementing the count in said counter means by one for each of the periodically occurring step signals when the control means is in the first state and for incrementing the count in the counter means by two for each of the periodically occurring step signals when said control means is in said second state. There are also included initializing means for clearing the counter means to a first count when the control means is in the first state and alternatively to the first count or to a second count when said control means is in the second state whereby the counter means counts by odd numbers or even numbers.

Abstract: In a keyboard there are a plurality of key operated variable capacitor switches acting as differentiators to change the widths of electrical pulses which are then integrated to give signals whose level indicate which switches have been operated. The gain and operating points of amplifiers can be changed to change the transfer function of the electronics and thus increase the mechanical hysteresis of the switches.

Abstract: A cathode ray tube (CRT) display system utilizing a parallel line raster scan displays characters formed from matrices of dots written during the parallel line scans. When the parallel lines are vertically displaced horizontal lines, the height of the characters is changed by switching between a sequential scan line raster and an interlaced scan line raster, and the width of the characters is changed by controlling the number of times each of the dots is sequentially displayed in its associated scan line.

Abstract: A capacitive switch includes: an electrical circuit formed by two spaced pads of conductive material on an insulative substrate; and a capacitive coupling member on the end of a keystem wherein the end of the keystem has a looped ribbon formed by two layers of insulating material sandwiching a layer of conductive material. As the keystem is urged toward the substrate a monotonically increasing area of the ribbon mechanically contacts the pads so that a monotonically increasing capacitive coupling is made between the two spaced pads.