The foundation of the GEM System^™ is a top quality PASS device. The Grace line of PASS products were designed to eliminate the problems caused by excessive false alerts, and utilize a solid state accelerometer to detect the lack of motion. Most other PASS manufacturers use mechanical devices to measure motion, either by way of a roller bearing crossing contact points, or a light chamber with a roller bearing that blocks the light signal. These types of accelerometers are subject to the ill effects of corrosion, condensation, and they may not work when the wearer's body is in certain positions.

    The solid state accelerometer, by contrast, uses the wearer's motion to generate an electrical charge that can be measured and timed. Analogous to the difference between a solid state television tuner and a mechanical television tuner, the solid state accelerometer is more durable and less prone to annoying false alerts.

    In order to achieve accurate and continuous accountability, an individually coded message is transmitted via spread spectrum radio technology to the GEM System's^™ Command Receiver where it is processed and translated into the emergency incident census. This radio technology was first developed for use in military and high-security applications because of the difficulty in intercepting and/or jamming the signal.

    Spread spectrum technology allows vast amounts of data to be transmitted accurately with little or no signal loss. Cellular telephones are an example of a communications application that utilizes the spread spectrum radio frequency.

    Utilizing frequencies in the 902 - 928 MHz band, the GEM System^™ transmits frequency agile signals in a hexadecimally configured sequence that hops through this frequency range. The signal encoding process makes this type of data transmission highly resistant to radio frequency (RF) "noise", such as interference from foreign signals, signal jamming, and electromagnetic fields.

    The signal is received at the base, or Command Receiver, where a proprietary processor translates the signal into readable data that can be displayed on the LCD display screen and/or an interfaced computer monitor (PC or laptop). Technology that was once reserved for the space program and the military is now available for the first time in the fire/rescue service.

Contact Grace Industries, Inc. to learn more obout our Solutions For Life Safety.