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35400 km above the equator. These Earth-orbiting systems are capable of receiving and relaying voice, data, and TV signals.
* Cellular and PCS systems use several radio communications technologies. The systems divide the region covered into multiple geographic areas. Each area has a low-power transmitter or radio relay antenna device to relay calls from one area to the next area.
* Radio and spread spectrum technologies - Wireless local area networks use a high-frequency radio technology similar

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