EAC - Voluntary Voting System Guidelines

Name : | James Johnson
Organization : | N/A
Post Date : | 9/30/2005
Section Comments
Section : | 6.7
Page no. : |
Line no.: |
Comment : | Wireless, what is it? Simply put, wireless is any communications method that does not depend on wires (metallic or fiber) for the transmission of communications signals. Wireless communications provides “connectivity” between two or more devices (a transmitter and a receiver) enabling them to exchange information. The fundamental difference between wireless communication and other “wired” forms of communications is the medium over which the encoded energy containing information is transferred between the transmitter and receiver. In wireless systems energy transfer occurs through air or through free space without a physical connection between the devices. The energy transfer can be visible optical radiation, invisible infrared, ultraviolet or radio frequency (RF) to name a few. The energy transferred between the two devices can follow a narrow path, essentially a straight line between origin (transmitter) and destination (receiver) – line of sight (LOS), and a diverging path or be sent out in all directions (omni directional). The radiated energy behaves in different ways depending on its frequency. Higher frequency signals such as light (optical) tend to be more directional whereas RF signal tend to be transmitted in all directions without the use of specially designed directional antennas. Another characteristic of the energy transmitted is its ability to penetrate solid objects. Optical signals do not penetrate solid objects unless they are transparent to that frequency of radiation, whereas RF signals (at lower frequencies) can flow freely through or around solid objects such as walls. Both optical and RF signals can bounce off various surfaces form walls, water, mirrors and buildings. [Statements submitted to NIST Technical Guidelines Development Committee]