ProSoft Technology RLXIB-IHN-W-E - Manual (Page 161)

RLXIB-IHN-WC ♦ 802.11n Glossary of Terms
Weatherproof Industrial Hotspot User Manual
ProSoft Technology, Inc. Page 161 of 161
July 9, 2012
RTU (Remote Terminal Unit)
Modbus transmission mode where each eight-bit byte in a message contains two
four-bit hexadecimal characters. There are two transmission modes (ASCII or
RTU). The main advantage of the RTU mode is that its greater character density
allows better data throughput than ASCII mode for the same baud rate; each
message is transmitted in a continuous stream (See also ASCII, above).
S
Sector Antenna
An antenna type that radiates in only a specific direction. Multiple sector
antennas are commonly used in point-to-multipoint situations.
Signal Diversity
A process by which two small dipole antennas are used to send and receive,
combining their results for better effect.
Signal Loss
The amount of signal strength that’s lost in antenna cable, connectors, and free
space. Signal loss is measured in decibels. Also referred to as gain loss.
Signal Strength
The strength of the radio waves in a wireless network.
Simplex
A communications circuit or system designed to either transmit data or receive
data, but not both. Broadcast television is an example of simplex communication
system. A television station sends a TV signal but cannot receive responses
back from the television sets to which it is transmitting. The TV sets can receive
the signal from the TV station but cannot transmit back to the station.
Site Survey
A comprehensive facility study performed by network managers to ensure that
planned service levels will be met when a new wireless LAN, or additional WLAN
segments to an existing network are deployed. Site survey’s are usually
performed by a radio frequency engineer and used by systems integrators to
identify the optimum placement of access points to ensure that planned levels of
service are met. Site surveys are sometimes conducted following the deployment
to ensure that the WLAN is achieving the necessary level of coverage. Site
surveys can also be used to detect rogue access points.
Spectrum
A range of electromagnetic frequencies.
Spread Spectrum
A form of wireless communication in which a signal’s frequency is deliberately
varied. This increases bandwidth and lessens the chances of interruption or
interception of the transmitted signal.