To enable the use of standard control (NON IS) fire panels in intrinsically safe systems, a device to “translate” voltage levels from the loop to levels compatible with the I.S. requirements is required. The PT971 also “boosts” the current pulses returned by the I.S. detectors.
The PT971 is a loop-powered device that draws a low quiescent current and is therefore transparent to both the loop driver and the I.S. detectors.