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: 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: 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.