The Physiological/Biological Transmission Beacon, also known simply as a Prothean Beacon, was the primary form of communication used universally across the Prothean Empire. The technology was developed specifically to tap directly into prothean physiology, allowing them to use their sensory ability to store memory-based information into the beacon for transmission. A larger and more powerful variant of the beacon also existed; the Prothean Library. After the Reapers wiped out the protheans, these beacons were some of the last remnants of what remained.