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“LIVE” Tech Vocabulary
Point to Point/P2P -A traditional point-to-point data link is a communications medium with exactly
two endpoints.
Point to Multi Point/P2MP/Multipoint
Point to Multipoint often refers to a system where one transceiver acts as the Master, managing the
functions of the overall system and two or more transceivers act as Slaves, receiving instructions and
performing based on the instruction of the master. You will also hear the terms Host and Subscriber.
Mesh
A type of networking where each node must not only capture and disseminate its own data from the
network, but also serve as a relay for other nodes, that is, it must collaborate to propagate the data in
the network.
Transceiver - A device, in this case radios, both send transmissions and receives transmissions.
Node -is a connection point, either a redistribution point or a communication endpoint
Bandwidth -the term is often used to describe the capacity of data that can retransferred across a
network in a prescribed period of time. Often also referred to as throughput
 56 kbit/s Modem / Dialup
 1.5 Mbit/s ADSL Lite
 1.544 Mbit/s T1/DS1
 10 Mbit/s Ethernet
 11 Mbit/s Wireless 802.11b
 44.736 Mbit/s T3/DS3
 54 Mbit/s Wireless 802.11g
 100 Mbit/s Fast Ethernet
 155 Mbit/s OC3
 600 Mbit/s Wireless 802.11n
 622 Mbit/s OC12
 1 Gbit/s Gigabit Ethernet
Relay/repeater-A device place between two nodes outside the range or line of sight of the other who's
function is only to listen and reproduce the signal from one node that it will be received by the other
node.
Frequency/Radio Frequency/RF-is a rate of oscillation in the range of about 3 kHz to 300 GHz,
which corresponds to the frequency of radio waves, and the alternating currents which carry radio
signals. RF usually refers to electrical rather than mechanical oscillations, although mechanical RF
systems do exist.
Microwave-Radio waves whose wavelengths are conveniently measured in small numbers of
centimeters; these are called microwaves. This part of the radio spectrum ranges across frequencies of
roughly 1.0 gigahertz (GHz) to 30 GHz. These correspond to wavelengths from 30 centimeters down
to 1.0 cm.
The next higher part of the radio electromagnetic spectrum, where the frequencies are above 30 GHz
and below 100 GHz, are called "millimeter waves" because their wavelengths are conveniently
measured in millimeters, and their wavelengths range from 10 mm down to 3.0 mm
Transmission-the process of sending, propagating and receiving an analogue or digital information
signal over a physical point-to-point or point-to-multipoint transmission medium, either wired, optical
fiber or wireless.
WLAN-Wireless LAN by IEEE 802.11, 802.11a, 802.11b, 802.11g, 802.11n
The Wireless Local Area Network (WLAN) technology is defined by the IEEE 802.11 family of
specifications. There are currently four specifications in the family: 802.11, 802.11a, 802.11b, and
802.11g. All four use the Ethernet protocol and CSMA/CA (carrier sense multiple access with collision
avoidance instead of CSMA/CD) for path sharing .
802.11 -- applies to wireless LANs and provides 1 or 2 Mbps transmission in the 2.4 GHz band using
either frequency hopping spread spectrum (FHSS) or direct sequence spread spectrum (DSSS).
802.11a -- an extension to 802.11 that applies to wireless LANs and provides up to 54 Mbps in the
5GHz band. 802.11a uses an orthogonal frequency division multiplexing (OFDM) encoding scheme
rather than FHSS or DSSS. The 802.11a specification applies to wireless ATM systems and is used in
access hubs.
802.11b (also referred to as 802.11 High Rate or Wi-Fi) -- an extension to 802.11 that applies to
wireless LANS and provides 11 Mbps transmission (with a fallback to 5.5, 2 and 1 Mbps) in the 2.4
GHz band. 802.11b uses only DSSS. 802.11b was a ratification to the original 802.11 standard,
allowing wireless functionality comparable to Ethernet.
802.11g -- offers wireless transmission over relatively short distances at 20 - 54 Mbps in the 2.4 GHz
band. The 802.11g also uses the OFDM encoding scheme.
802.11n - builds upon previous 802.11 standards by adding MIMO (multiple-input multiple-output).
IEEE 802.11n offers high throughput wireless transmission at 100Mbps – 200 Mbps.
Protocol-is a system of digital message formats and rules for exchanging those messages in or
between computing systems and in telecommunications. A protocol may have a formal description.
Line of Sight (LOS)-refers to electro-magnetic radiation or acoustic wave propagation.
Electromagnetic transmission includes light emissions traveling in a straight line. The rays or waves
may be diffracted, refracted, reflected, or absorbed by atmosphere and obstructions with material and
generally cannot travel over the horizon or behind obstacles.
Line of sight propagation to an antenna
At low frequencies (below approximately 2 MHz or so) radio signals travel as ground waves, which
follow the Earth's curvature due to diffraction with the layers of atmosphere. This enables AM radio
signals in low-noise environments to be received well after the transmitting antenna has dropped below
the horizon. Additionally, frequencies between approximately 1 and 30 MHz, can be reflected by the
F1/F2 Layer, thus giving radio transmissions in this range a potentially global reach (see shortwave
radio), again along multiply deflected straight lines. The effects of multiple diffraction or reflection
lead to macroscopically "quasi-curved paths".
However, at higher frequencies and in lower levels of the atmosphere, neither of these effects are
significant. Thus any obstruction between the transmitting antenna and the receiving antenna will
block the signal, just like the light that the eye may sense. Therefore, since the ability to visually see a
transmitting antenna (disregarding the limitations of the eye's resolution) roughly corresponds to the
ability to receive a radio signal from it, the propagation characteristic of high-frequency radio is called
"line-of-sight". The farthest possible point of propagation is referred to as the "radio horizon".
In practice, the propagation characteristics of these radio waves vary substantially depending on the
exact frequency and the strength of the transmitted signal (a function of both the transmitter and the
antenna characteristics). Broadcast FM radio, at comparatively low frequencies of around 100 MHz,
are less affected by the presence of buildings and forests.
Interference -Electromagnetic interference (or EMI, also called radio frequency interference or RFI) is
disturbance that affects an electrical circuit due to either electromagnetic induction or electromagnetic
radiation emitted from an external source. The disturbance may interrupt, obstruct, or otherwise
degrade or limit the effective performance of the circuit.
Co-channel interference or CCI is crosstalk from two different radio transmitters using the same
frequency. There can be several causes of co-channel radio interference; four examples are listed here.
• Cellular Mobile Networks
• Adverse weather conditions
• Poor frequency planning
• Overly-crowded radio spectrum
Adjacent-channel interference or ACI is interference caused by extraneous power from a signal in an
adjacent channel. ACI may be caused by inadequate filtering, such as incomplete filtering of unwanted
modulation products in frequency modulation (FM) systems, improper tuning, or poor frequency
control, in either the reference channel or the interfering channel, or both. ACI is distinguished from
crosstalk.
Bluetooth-is a proprietary open wireless technology standard for exchanging data over short distances
(using short wavelength radio transmissions in the ISM band from 2400-2480 MHz) from fixed and
mobile devices, creating personal area networks (PANs) with high levels of security. Often used
between computers, or computers and headsets, speakers and microphones.
POE/injector-Power over Ethernet-a system to pass electrical power safely, along with data, on
Ethernet cabling.
Decibels/dB-is a logarithmic unit that indicates the ratio of a physical quantity (usually power or
intensity) relative to a specified or implied reference level. A ratio in decibels is ten times the
logarithm to base 10 of the ratio of two power quantities. A decibel is one tenth of a bel, a seldom-used
unit.
The decibel is used for a wide variety of measurements in science and engineering, most prominently
in acoustics, electronics, and control theory. In electronics, the gains of amplifiers, attenuation of
signals, and signal-to-noise ratios are often expressed in decibels. The decibel confers a number of
advantages, such as the ability to conveniently represent very large or small numbers, and the ability to
carry out multiplication of ratios by simple addition and subtraction.
ERIP-In radio communication systems, Equivalent isotropically radiated power (EIRP) or,
alternatively, Effective isotropically radiated power is the amount of power that a theoretical isotropic
antenna (which evenly distributes power in all directions) would emit to produce the peak power
density observed in the direction of maximum antenna gain. EIRP can take into account the losses in
transmission line and connectors and includes the gain of the antenna. The EIRP is often stated in
terms of decibels over a reference power emitted by an isotropic radiator with an equivalent signal
strength. The EIRP allows comparisons between different emitters regardless of type, size or form.
From the EIRP, and with knowledge of a real antenna's gain, it is possible to calculate real power and
field strength values.
Watts-is a derived unit of power in the International System of Units (SI), named after the Scottish
engineer James Watt (1736–1819). The unit, defined as one joule per second, measures the rate of
energy conversion.
 10−3 W mW milliwatt
 10−6 W µW microwatt
 10−12 W pW picowatt
 101 W daW decawatt
 102 W hW hectowatt
 103 W kW kilowatt
 106 W MW megawatt
 109 W GW gigawatt
Milliwatts-The milliwatt is equal to one thousandth (10−3) of a watt. A typical laser pointer outputs
about five milliwatts of light power, whereas a typical hearing aid for people consumes less than one
milliwatt.
Networking-is a collection of terminals, links and nodes which connect together to enable
telecommunication between users of the terminals. Each terminal in the network must have a unique
address so messages or connections can be routed to the correct recipients. The collection of addresses
in the network is called the address space.
Broadcast
is a one-way wireless transmission over radio waves intended to reach a wide audience. Stations can be
linked in networks to broadcast a common format or simulcast or both. Broadcasting also can be done
via cable radio, local wire television networks, satellite, and Internet via streaming media on the
Internet.
Unicast
The term unicast is contrasted with the term broadcast which means
transmitting the same data to all possible destinations. Unicast messaging is used for all network
processes in which a private or unique resource is requested.
Certain network applications which are mass-distributed are too costly to be conducted with unicast
transmission since each network connection consumes computing resources on the sending host and
requires its own separate network bandwidth for transmission. Such applications include streaming
media of many forms. Internet radio stations using unicast connections may have high bandwidth
costs.
Multicast
A multi-destination distribution method, multicasting, sends
data only to interested destinations by using special address assignments. is the delivery of a message
or information to a group of destination computers simultaneously in a single transmission from the
source creating copies automatically in other network elements, such as routers, only when the
topology of the network requires it.
Multicast is most commonly implemented in IP multicast, which is often employed in Internet Protocol
(IP) applications of streaming media and Internet television.
Static Address-Static IP addresses are manually assigned to a computer by an administrator. The exact
procedure varies according to platform.
DHCP-dynamic IP addresses, which are assigned either by the computer interface or host software
itself or assigned by a server using Dynamic Host Configuration Protocol (DHCP). Even though IP
addresses assigned using DHCP may stay the same for long periods of time, they can generally change.
Gateway or Default Router-In computer networking, a gateway is a node (a router) on a TCP/IP
network that serves as an access point to another network. A default gateway is the node on the
computer network that the network software uses when an IP address does not match any other routes
in the routing table. In home computing configurations, an ISP often provides a physical device, which
both connects local hardware to the Internet and serves as a gateway. Such devices include DSL
modems and cable modems.
Subnet Mask-or subnet, is a logically visible subdivision of an IP network. The practice of dividing a
network into subnetworks is called subnetting. All computers that belong to a subnet are addressed
with a common, identical, most-significant bit-group in their IP address. This results in the logical
division of an IP address into two fields, a network or routing prefix and the rest field. The rest field is
a specific identifier for the computer or the network interface.
example, 255.255.255.0 is the network mask for the 192.168.1.0/24 prefix.
ISP-is a company that provides access to the Internet. Access ISPs directly connect customers to the
Internet using copper wires, wireless or fiber-optic connections.
Latency-a measure of the time delay experienced by a system. As in a movie, when the voice is not
synchronized with the movement of the mouth.
Bottleneck-is a phenomenon where the performance or capacity of an entire system is limited by a
single or limited number of components or resources. The term bottleneck is taken from the 'assets are
water' metaphor. As water is poured out of a bottle, the rate of outflow is limited by the width of the
conduit of exit—that is, bottleneck.
Telepresence-refers to a set of technologies which allow a person to feel as if they were present, to
give the appearance of being present, or to have an effect, via telerobotics, at a place other than their
true location. A popular application is found in telepresence videoconferencing, the highest possible
level of videotelephony. Telepresence via video deploys greater technical sophistication and improved
fidelity of both sight and sound than in traditional videoconferencing.
Ping--is a computer network administration utility used to test the reachability of a host on an Internet
Protocol (IP) network and to measure the round-trip time for messages sent from the originating host to
a destination computer. The name comes from active sonar terminology. Ping operates by sending
Internet Control Message Protocol (ICMP) echo request packets to the target host and waiting for an
ICMP response. In the process it measures the time from transmission to reception (round-trip time)
and records any packet loss.
Ipconfig-(internet protocol configuration) in Microsoft Windows is a console application that displays
all current TCP/IP network configuration values and can Dynamic Host Configuration Protocol DHCP
and Domain Name System DNS settings.
Ifconfig-is a system administration utility in Unix-like operating systems to configure, control, and
query TCP/IP network interface parameters from a command line interface (CLI) or in system
configuration scripts. Ifconfig originally appeared in 4.2BSD as part of the BSD TCP/IP suite.
Traceroute-is a computer network diagnostic tool for displaying the route (path) and measuring transit
delays of packets across an Internet Protocol (IP) network traceroute outputs the list of traversed
routers in simple text format, together with timing information Traceroute is available on most
operating systems.
On Microsoft Windows operating systems it is named tracert.
Video resolution-Analog television systems use interlaced video scanning with two sequential scans
called fields (50 PAL or 60 NTSC fields per second), one with the odd numbered scan lines, the other
with the even numbered scan lines to give a complete picture or frame (25 or 30 frames per second).
This is done to save transmission bandwidth but a consequence is that in picture tube (CRT) displays,
the full vertical resolution cannot be realized. For example, the maximum detail in the vertical
direction would be for adjacent lines to be alternately black then white. This is not as great a problem
in a progressive video display but an interlace display will have an unacceptable flicker at the slower
frame rate. This is why interlace is unacceptable for fine detail such as computer word processing or
spreadsheets.
Fixed pixel array displays such as LCDs, plasmas, DLPs, LCoS, etc. need a "video scaling" processor
with frame memory, which, depending on the processing system, effectively converts an incoming
interlaced video signal into a progressive video signal. A similar process occurs in a PC and its display
with interlaced video (e.g., from a TV tuner card). The downside is that interlace motion artifacts are
almost impossible to remove resulting in horizontal "toothed" edges on moving objects.
Televisions are of the following resolutions:
• Standard-definition television (SDTV):
◦
480i (NTSC standard uses an analog system of 486i split into two interlaced fields of 243
lines)
◦
576i (PAL, 720×576 split into two interlaced fields of 288 lines)
• Enhanced-definition television (EDTV):
◦
480p (720×480 progressive scan)
◦
576p (720×576 progressive scan)
• High-definition television (HDTV):
◦
720p (1280×720 progressive scan)
◦
1080i (1920×1080 split into two interlaced fields of 540 lines)
◦
1080p (1920×1080 progressive scan)
Code Name Aspect ratio Width Height
XGA eXtended Graphics Array 4:3 1024x768
XGA+ eXtended Graphics Array Plus 4:3 1152x864
WXGA Widescreen eXtended Graphics Array 16:9 1280x720
WXGA Widescreen eXtended Graphics Array 16:10 1280x800
SXGA (UVGA) Super eXtended Graphics Array 4:3 1280x960
SXGA Super eXtended Graphics Array 5:4 1280x1024
HD High Definition 16:9 1360x768
HD High Definition 16:9 1366x768
WXGA+ Widescreen eXtended Graphics Array Plus 16:10 1440x900
HD+ High Definition Plus 16:9 1600x900
UXGA Ultra eXtended Graphics Array 4:3 1600x1200
WSXGA+ Widescreen Super eXtended Graphics Array Plus 16:10 1680x1050
FHD (Full HD) Full High Definition 16:9 1920x1080
WUXGA Widescreen Ultra eXtended Graphics Array 16:10 1920x1200
QFHD Quad Full High Definition 16:9 2560x1440
Progressive Scanning-(alternatively referred to as noninterlaced scanning) is a way of displaying,
storing, or transmitting moving images in which all the lines of each frame are drawn in sequence. This
is in contrast to interlaced video used in traditional analog television systems where only the odd lines,
then the even lines of each frame (each image called a video field) are drawn alternately. The system
was originally known as "sequential scanning" (a more technically correct description)
Firewire-The IEEE 1394 interface is a serial bus interface standard for high-speed communications
and isochronous real-time data transfer, frequently used by personal computers, as well as in digital
audio, digital video, automotive, and aeronautics applications. The interface is also known by the brand
names of FireWire (Apple), i.LINK (Sony), and Lynx (Texas Instruments).
USB-(Universal Serial Bus) is an industry standard developed in the mid-1990s that defines the cables,
connectors and protocols used for connection, communication and power supply between computers
and electronic devices. USB was designed to standardize the connection of computer peripherals, such
as keyboards, pointing devices, digital cameras, printers, portable media players, disk drives and
network adapters to personal computers, both to communicate and to supply electric power. It has
become commonplace on other devices, such as smartphones, PDAs and video game consoles. USB
has effectively replaced a variety of earlier interfaces, such as serial and parallel ports, as well as
separate power chargers for portable devices. Up to 2008, about 2 billion USB devices were sold each
year, and approximately 6 billion devices were sold in total.
Thunderbolt-(originally codenamed Light Peak) is an interface for connecting peripheral devices to a
computer via an expansion bus. Thunderbolt was developed by Intel and brought to market with
technical collaboration from Apple Inc. It was introduced commercially on Apple's updated MacBook
Pro lineup on February 24, 2011, using the same port and connector as Mini DisplayPort. Though
initially registered with Apple Inc., full rights of the Thunderbolt technology trademark belong to Intel
Corp., and subsequently led to the transfer of the registration.
Thunderbolt essentially combines PCI Express and DisplayPort into a new serial data interface that can
be carried over longer and less costly cables. Because PCI Express is widely supported by device
vendors and built into most of Intel's modern chipsets, Thunderbolt can be added to existing products
with relative ease. Thunderbolt driver chips fold the data from these two sources together, and split
them back apart again for consumption within the devices. This makes the system backward
compatible with existing DisplayPort hardware upstream of the driver.
Composite Video-is the format of an analog television (picture only) signal before it is combined with
a sound signal and modulated onto an RF carrier. In contrast to component video (YPbPr) it contains
all required video information, including colors in a single line-level signal. Like component video,
composite-video cables do not carry audio and are often paired with audio cables.
Composite video is often designated by the CVBS initialism, meaning "Composite Video, Blanking,
and Sync." It is usually in standard formats such as NTSC, PAL, and SECAM.
Component Video
In a composite signal, the luminance, Brightness (Y) signal and the chrominance, Color (C) signals are
encoded together into one signal. When the color components are kept as separate signals, the video is
called component analog video (CAV), which requires three separate signals: the luminance signal (Y)
and the color difference signals (R-Y & B-Y). Component video does not undergo the encoding
process, the color quality is noticeably better than composite video. Component video connectors are
not unique in that the same connectors are used for several different standards; hence, making a
component video connection often does not lead to a satisfactory video signal being transferred. Many
DVD players and TVs may need to be set to indicate the type of input/output being used, and if set
incorrectly the image may not be properly displayed. Progressive scan, for example, is often not
enabled by default, even when component video output is selected.
HDMI-(High-Definition Multimedia Interface) is a compact audio/video interface for transmitting
uncompressed digital data. It is a digital alternative to consumer analog standards, such as radio
frequency (RF) coaxial cable, composite video, Audio signal Dolby Digital, DVD-Audio, Super Audio
CD, Dolby Digital Plus, Dolby TrueHD, DST Video signal 480i, 480p, 576i, 576p, 720p, 1080i,
1080p, 1440p, 1600p, 2160p,
RCA connector
sometimes called a phono connector or cinch connector, is a type of electrical connector commonly
used to carry audio and video signals. The name "RCA" derives from the Radio Corporation of
America, which introduced the design by the early 1940s to allow mono phonograph players to be
connected to amplifiers.
They began to replace the older TRS connectors (also called jack plugs) for many other applications in
the audio world when component high fidelity systems started becoming popular in the 1950s.
However, mini TRS connectors (3.5 mm jacks) and sub-miniature (2.5 mm) jacks are predominant in
personal stereo systems.
Analog
or analogue signal is any continuous signal for which the time varying feature (variable) of the signal
is a representation of some other time varying quantity, i.e., analogous to another time varying signal.
It differs from a digital signal in terms of small fluctuations in the signal which are meaningful. Analog
is usually thought of in an electrical context; however, mechanical, pneumatic, hydraulic, and other
systems may also convey analog signals. In sound recording, fluctuations in air pressure (that is to say,
sound) strike the diaphragm of a microphone which induces corresponding fluctuations in the current
produced by a coil in an electromagnetic microphone, or the voltage produced by a condenser
microphone. The voltage or the current is said to be an "analog" of the sound.
Digital
All digital information possesses common properties that distinguish it from analog communications
methods:
• Synchronization: Since digital information is conveyed by the sequence in which symbols are
ordered, all digital schemes have some method for determining the beginning of a sequence. In
written or spoken human languages synchronization is typically provided by pauses (spaces),
capitalization, and punctuation. Machine communications typically use special synchronization
sequences.
• Language: All digital communications require a language, which in this context consists of all the
information that the sender and receiver of the digital communication must both possess, in
advance, in order for the communication to be successful. Languages are generally arbitrary
and specify the meaning to be assigned to particular symbol sequences, the allowed range of
values, methods to be used for synchronization, etc.
• Errors: Disturbances (noise) in analog communications invariably introduce some, generally small
deviation or error between the intended and actual communication. Disturbances in a digital
communication do not result in errors unless the disturbance is so large as to result in a symbol
being misinterpreted as another symbol or disturb the sequence of symbols. It is therefore
generally possible to have an entirely error-free digital communication. Further, techniques
such as check codes may be used to detect errors and guarantee error-free communications
through redundancy or retransmission. Errors in digital communications can take the form of
substitution errors in which a symbol is replaced by another symbol, or insertion/deletion errors
in which an extra incorrect symbol is inserted into or deleted from a digital message.
Uncorrected errors in digital communications have unpredictable and generally large impact on
the information content of the communication.
• Copying: Because of the inevitable presence of noise, making many successive copies of an analog
communication is infeasible because each generation increases the noise. Because digital
communications are generally error-free, copies of copies can be made indefinitely.
• Granularity: When a continuously variable analog value is represented in digital form there is always
a decision as to the number of symbols to be assigned to that value. The number of symbols
determines the precision or resolution of the resulting datum. The difference between the actual
analog value and the digital representation is known as quantization error. Example: the actual
temperature is 23.234456544453 degrees but if only two digits (23) are assigned to this
parameter in a particular digital representation (e.g. digital thermometer or table in a printed
report) the quantizing error is: 0.234456544453. This property of digital communication is
known as granularity.