According to George Epstein “Computer is an electronic device that performs calculation and processes information. It handles vast amount of facts and figures and solves complex problems at incredibility high speeds. A computer can processes many kinds of information, from book titles and customers account numbers to chemical formulas and words from ancient Greek texts. It handles all such data in the form of numbers.
Retired General Melchor P. Rosales, administrator of the Office of Civil Defense and executive officer of the NDCC, during his speech at the 2003 Philippine ESRI GIS user conference, said that, “being a disaster-prone country, we face a lot of natural and man-made hazards, and GIS has become a very important tool in helping us respond effectively, as SMS becomes part of the Filipinos way of communicating information, it will be an effective tool in reporting disasters. (Valdez, 2003)
Wireless communications have been employed for data transmission for a long time. Until recently, most of its applications in computer networks were bound to a fixed variant. Network users and even network architects are not always aware that at certain fragments of the network path, information is not being transmitted through wires. Instead, it is propagated through the Earth’s atmosphere or space in the form of electromagnetic waves. This might happen when a computer network leases a channel from a communications carrier and the specific link of such a channel is a satellite or terrestrial microwave link.
Reference: COMPUTER NETWORKS principles, technologies and protocols for network design by Natalia Olifer and Victor Olifer