Coaxial

The important characteristics of IR is that it can’t penetrate walls or other opaque materials. Typically, with an IR-based system, a receiver is placed in every location in which a tagged device might be found. The tagged device emits IR light, and if the tagged device is in the same room as a receiver its position is known. The major advantage of an IR-based system is that as the oldest and most installed positioning technology, solutions are generally available from a variety of sources…

the center of the composite cylindrical glass fiber, the core as if it is guided down the core in a zigzag path of successive reflections. These light waves are guided through the core of the optical fiber just like a radio frequency signal in a coaxial…

While ubiquitous Internet access is extremely convenient and enables marvelous new applications for mobile users, it also creates a major security vulnerability—by placing a passive receiver in the vicinity of the wireless transmitter, that receiver can obtain a copy of every packet that is transmitted! These packets can contain all kinds of sensitive information, including passwords, social security numbers, trade secrets, and private personal messages. A passive receiver that records a copy of…