TB9400/TN9275 Installation and Operation 153
© Tait International Limited May 2023
TaitNet
Brand name for a PMR network designed and manufactured by Tait 
International Limited.
TCP Transmission Control Protocol. A complex protocol on top of IP for 
sending reliable streams of data with flow control.
TDMA Time Division Multiple Access. TDMA divides a single RF channel into 
multiple time slots (logical channels), with each time slot being transmitted 
in rapid succession, one after the other. A time slot can be occupied by a 
single voice or data stream.
TIA Telecommunications Industry Association
toggle Describes the switching between two states. If something is on, toggling it 
turns it off. If it is off, toggling it turns it on.
tone A sound wave of a particular frequency.
Tx Transmitter.
uplink The transmission path from SUs to fixed equipment.
UTC Coordinated Universal Time (word order from French). An international 
time standard that has replaced Greenwich Mean Time.
voice stream A digitized voice signal that passes through the main switch.
VoIP Voice over IP. The name for the technology that puts speech signals in 
packets and then routes them over an IP backbone network.
voting The systematic sampling of a group of channels for the channel with the 
best signal quality. Voting provides wide-area coverage and ensures that as 
the user moves throughout the coverage area the strongest channel is 
always available for a call.
VPN Virtual Private Network. A private communications network used to 
communicate confidentially over a non-private network.
VSWR Voltage Standing Wave Ratio is the ratio of the maximum peak voltage 
anywhere on the transmission line to the minimum value anywhere on the 
transmission line. A perfectly matched line has a VSWR of 1:1. A high 
ratio indicates that the antenna subsystem is poorly matched.