The AlcoSensor IV is protected from RFI (Radio frequency interference) by the shielding built into the case. Additionally there is an RFI detection circuit that will alert the operator if it detects any RFI, and the test is voided. When this happens, it is recommended that the operator locates the source, (two way radio, cell phone, etc.) and removes it from the immediate area. If this is not possible, the operator can try to move to a new location and begin testing again.

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