RSSI measures the strength of wireless signals received by devices. RSSI is expressed in dBm and calculated by subtracting path loss from transmitter power. Path loss affects signal strength due to obstacles and reflections
Antenna gain combines directivity and radiation efficiency. Gain describes power conversion in transmitting or receiving antennas. Gain is expressed in decibels (dBi) or decibels relative to dipole (dBd)
Telematics combines telecommunications, vehicular technologies, and computer science. Term coined by Simon Nora and Alain Minc in 1978 for information transfer. Originally meant telecommunications, now primarily refers to vehicle telematics
Telex emerged in Germany in 1926 as research program, became operational in 1933. System allows text-based messages over telephone lines using binary signals. Operates on switched station-to-station basis with teleprinter devices. Messages encoded onto paper tape at 50 baud speed
Multiplexing combines multiple signals into one over shared medium. Originated in telegraphy in 1870s, developed by George Owen Squier in 1910. Divides communication channel capacity into logical channels
X band spans 7.0-11.2 GHz in communication engineering. IEEE specifies radar range as 8.0-12.0 GHz