The JA-151IR four-beam infra-red optical barrier is designed for the indication of a breach into a protected area. The barrier is a product by Optex supplemented with transmitters compatible with the JABLOTRON 100+. The device is equipped with a 4-ray optical part with a high immunity against false alarms and the detection of small animals. The barrier occupies two positions in the system. The transmitters regularly perform automatic tests and report their status to the system. The barrier should be installed by a trained technician with a valid certificate issued by an authorised distributor.