Elements of Competence and Performance Criteria
Elements of Competence and Performance Criteria
Elements of Competence and Performance Criteria
Hours: 70
L.O 1.1 Study the environmental requirements according to the work to be done.
CCTV cameras are becoming more and more popular in the Rwanda amongst people
who place the safety of their family and property at a premium. Getting CCTV installed
has never been as accessible as it is now and there is an ever expanding choice of
CCTV cameras, kits and packages available. That means it can be difficult to know
which sort of cameras are best for you. One of the most fundamental things that you
need to understand is the difference between indoor and outdoor CCTV cameras.
Indoor CCTV cameras tend to be smaller and more lightweight than their outdoor
counterparts. The internal wiring s and features tend to the same and their more
lightweight design is thanks to the fact they are not exposed to the weather or tampering
by potential burglars.
Outdoor CCTV cameras are made of more durable materials than indoor cameras and
are heavier and much more robust to withstand the elements and to protect the camera
within from tampering. Some may even be housed in casing to protect them.
Dome cameras can often be used both indoors and outdoors. Cameras are housed
inside a dome that is both to ensure it is protected from the elements and to stop
onlookers knowing exactly where the camera is pointing.
When deciding what sort of CCTV cameras to install, we always advise you to seek the
help of a CCTV expert who will ensure that you get the right cameras for your needs.
Coverage area of a camera is what you can/want to see on screen (result). You need to
select your camera based on your requirement (wider or narrow, long or short distance).
In photography, angle of view (AOV)[1] describes the angular extent of a given scene
that is imaged by a camera. It is used interchangeably with the more general term field
of view. It is important to distinguish the angle of view from the angle of coverage,
which describes the angle range that a lens can image. Typically the image
circle produced by a lens is large enough to cover the film or sensor completely,
possibly including some vignetting toward the edge. If the angle of coverage of the lens
does not fill the sensor, the image circle will be visible, typically with strong vignetting
toward the edge, and the effective angle of view will be limited to the angle of coverage.
TEMPERATURE
Temperature is a physical quantity expressing hot and cold. It is a proportional measure of the
average kinetic energy of the random motions of the constituent particles of matter (such
as atoms and molecules) in a system.
HUMIDITY
Humidity is a term used to describe the amount of water vapor present in air. Water vapor, the
gaseous state of water, is generally invisible to the human eye.[1] Humidity indicates the likelihood
for precipitation, dew, or fog to be present. The amount of water vapor needed to achieve saturation
increases as the temperature increases
ANALOG CCTV
IP CCTV CAMERA
Hybrid CCTV systems combine IP and analog video, and can be a great way
to transition an analog system to IP without needing to replace all of the
existing cameras. Many NVR boxes on the market today are actually Hybrids
in that they accept analog cameras, and IP cameras and combine them onto
a single platform for the user.
1. What are the classifications of CCTV cameras based on the environmental requirement?
2. What are the installation requirements for indoor CCTV camera system?
3. What are the installation requirements for outdoor CCTV camera system?
4. What are the adequateS information about environmental requirements study?
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L.O 1.2 Identify the network structure and devices according to their types and specifications
BUS Topology
Bus topology is a network type in which every computer and network device is
connected to single cable. When it has exactly two endpoints, then it is called Linear
Bus topology.
1. It is cost effective.
2. Cable required is least compared to other network topology.
3. Used in small networks.
4. It is easy to understand.
5. Easy to expand joining two cables together.
RING Topology
It is called ring topology because it forms a ring as each computer is connected to
another computer, with the last one connected to the first. Exactly two neighbours for
each device.
1. A number of repeaters are used for Ring topology with large number of nodes, because
if someone wants to send some data to the last node in the ring topology with 100
nodes, then the data will have to pass through 99 nodes to reach the 100th node.
Hence to prevent data loss repeaters are used in the network.
2. The transmission is unidirectional, but it can be made bidirectional by having 2
connections between each Network Node, it is called Dual Ring Topology.
3. In Dual Ring Topology, two ring networks are formed, and data flow is in opposite
direction in them. Also, if one ring fails, the second ring can act as a backup, to keep the
network up.
4. Data is transferred in a sequential manner that is bit by bit. Data transmitted, has to
pass through each node of the network, till the destination node.
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1. Transmitting network is not affected by high traffic or by adding more nodes, as only the
nodes having tokens can transmit data.
2. Cheap to install and expand
STAR Topology
In this type of topology all the computers are connected to a single hub through a cable.
This hub is the central node and all others nodes are connected to the central node.
MESH Topology
It is a point-to-point connection to other nodes or devices. All the network nodes are
connected to each other. Mesh has n(n-1)/2 physical channels to link n devices.
There are two techniques to transmit data over the Mesh topology, they are :
1. Routing
2. Flooding
1. Partial Mesh Topology: In this topology some of the systems are connected in the
same fashion as mesh topology but some devices are only connected to two or three
devices.
2. Full Mesh Topology: Each and every nodes or devices are connected to each other.
1. Fully connected.
2. Robust.
3. Not flexible.
TREE Topology
It has a root node and all other nodes are connected to it forming a hierarchy. It is also
called hierarchical topology. It should at least have three levels to the hierarchy.
1. Heavily cabled.
2. Costly.
3. If more nodes are added maintenance is difficult.
4. Central hub fails, network fails.
HYBRID Topology
It is two different types of topologies which is a mixture of two or more topologies. For
example if in an office in one department ring topology is used and in another star
topology is used, connecting these topologies will result in Hybrid Topology (ring
topology and star topology).
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4. Flexible.
1. Complex in design.
2. Costly.
1. Simplex Mode
2. Half duplex Mode
3. Full duplex Mode
SIMPLEX Mode
In this type of transmission mode, data can be sent only in one direction i.e.
communication is unidirectional. We cannot send a message back to the sender.
Unidirectional communication is done in Simplex Systems where we just need to send a
command/signal, and do not expect any response back.
For example, on a local area network using a technology that has half-duplex
transmission, one workstation can send data on the line and then immediately receive
data on the line from the same direction in which data was just transmitted. Hence half-
duplex transmission implies a bidirectional line (one that can carry data in both
directions) but data can be sent in only one direction at a time.
Example of half duplex is a walkie- talkie in which message is sent one at a time but
messages are sent in both the directions.
In full duplex system there can be two lines one for sending the data and the other for
receiving data.
LOGICAL TPLOGY
A logical topology is a concept in networking that defines the architecture of the
communication mechanism for all nodes in a network. Using network equipment such
as routers and switches, the logical topology of a network can be dynamically
maintained and reconfigured.
PEER TO PEER
Stands for "Peer to Peer." In a P2P network, the "peers" are computer systems which
are connected to each other via the Internet. Files can be shared directly between
systems on the network without the need of a central server. In other words, each
computer on a P2P network becomes a file server as well as a client.
CLIENT SERVER
Client/server network: A computer network in which one centralized, powerful
computer (called the server) is a hub to which many less powerful personal computers
or workstations (called clients) are connected. The clients run programs and access
data that are stored on the server. Compare peer-to-peer network.
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An IP address consists of four numbers; each can contain one to three digits. These
numbers are separated with a single dot (.). These four numbers can range from 0 to
255.
Types of IP addresses
The IP addresses can be classified into two. They are listed below.
Static IP Addresses
As the name indicates, the static IP addresses usually never change but they may be
changed as a result of network administration. They serve as a permanent Internet
address and provide a simple and reliable way for the communication. From the static
IP address of a system, we can get many details such as the continent, country, region
and city in which a computer is located, The Internet Service Provider (ISP) that serves
that particular computer and non-technical information such as precise latitude and
longitude of the country, and the locale of the computer. There are many websites
providing IP address lookups.
Dynamic IP Addresses
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Dynamic IP addresses are the second category. These are temporary IP addresses.
These IP addresses are assigned to a computer when they get connected to the
Internet each time. They are actually borrowed from a pool of IP addresses, shared over
various computers. Since limited number of static IP addresses are available, ISPs
usually reserve the portion of their assigned addresses for sharing among their
subscribers in this way.
Static IP addresses are considered as less secure than dynamic IP addresses because
they are easier to track.
The two versions of IP addresses currently running are IP versions 4 (IPv4) and IP
versions 6 (IPv6). There are many features with these two versions.
IP Version 6
The IPv6 is the most recent version of Internet Protocol. As the Internet is growing
rapidly, there is a global shortage for IPv4. IPv6 was developed by the Internet
Engineering Task Force (IETF). IPv6 is intended to replace the IPv4. IPv6 uses a 128-
bit address and it allows 2128 i.e. approximately 3.4×1038 addresses. The actual number
is slightly smaller as some ranges are reserved for special use or not used. The IPv6
addresses are represented by 8 groups of four hexadecimal digits with the groups being
supported by colons. An example is given below:
Eg: 2001:0db8:0000:0042:0000:8a2e:0370:7334
7) IPv6 follows the key design principles of IPv4 and so that the transition from IPv4 to
IPv6 is smoother.
These are the key features of the IPv6 when compared to the IPv4. However, IPv6 has
not become popular as IPv4.
IP Version 4
IP Version 4 (IPv4) was defined in 1981. It has not undergone much changes from that
time. Unfortunately, there is a need of IP addresses more than IPv4 could supply.
This is a little more than four billion IP addresses. An IPv4 address is typically formatted
as four 8-bit fields. Each 8-bit field represents a byte of the IPv4 address. As we have
seen earlier, each fields will be separated with dots. This method of representing the
byte of an IPv4 address is referred to as the dotted-decimal format. The bytes of the
IPv4 is further classified into two parts. The network part and the host part.
Network Part
This part specifies the unique number assigned to your network. It also identifies the
class of network assigned. The network part takes two bytes of the IPv4 address.
Host Part
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This is the part of the IPv4 address that you can assign to each host. It uniquely
identifies this machine on your network. For all hosts on your network, the network part
of the IP address will be the same and host part will be changing.
The IP hierarchy contains many classes of the IP addresses. Broadly, the IPv4
addressing system is divided into five classes of IP address. All the five classes are
identified by the first octet of the IP address.
1) Class A address
2) Class B address
3) Class C address
4) Class D address
5) Class E address
Class A Address
The first bit of the first octet is always set to zero. So that the first octet ranges from 1 –
127. The class A address only include IP starting from 1.x.x.x to 126.x.x.x. The IP range
127.x.x.x is reserved for loop back IP addresses. The default subnet mask for class A IP
address is 255.0.0.0. This means it can have 126 networks (27-2) and 16777214 hosts
(224-2). Class A IP address format is
thus: 0NNNNNNN.HHHHHHHH.HHHHHHHH.HHHHHHHH.
Class B Address
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Here the first two bits in the first two bits is set to zero. Class B IP Addresses range from
128.0.x.x to 191.255.x.x. The default subnet mask for Class B is 255.255.x.x. Class B
has 16384 (214) Network addresses and 65534 (216-2) Host addresses. Class B IP
address format is: 10NNNNNN.NNNNNNNN.HHHHHHHH.HHHHHHHH
Class C Address
The first octet of this class has its first 3 bits set to 110. Class C IP addresses range
from 192.0.0.x to 223.255.255.x. The default subnet mask for Class C is 255.255.255.x.
Class C gives 2097152 (221) Network addresses and 254 (28-2) Host addresses. Class
C IP address format is: 110NNNNN.NNNNNNNN.NNNNNNNN.HHHHHHHH
Class D Address
The first four bits of the first octet in class D IP address are set to 1110. Class D has IP
address rage from 224.0.0.0 to 239.255.255.255. Class D is reserved for Multicasting.
In multicasting data is not intended for a particular host, but multiple ones. That is why
there is no need to extract host address from the class D IP addresses. The Class D
does not have any subnet mask.
Class E Address
The class E IP addresses are reserved for experimental purpose only for R&D or study.
IP addresses in the class E ranges from 240.0.0.0 to 255.255.255.254. This class too is
not equipped with any subnet mask.
SWITCH
A network switch (also called switching hub, bridging hub, officially MAC bridge) is a
computer networking device that connects devices together on a computer network by
using packet switching to receive, process, and forward data to the destination device.
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ACCESS POINT
An access point is a device, such as a wireless router, that allows wireless devices to
connect to a network. Most access points have built-in routers, while others must be
connected to a router in order to provide network access.
NETWORK MEDIA
Network media is the actual path over which an electrical signal travels as it moves
from one component to another. This chapter describes the common types
of network media, including twisted-pair cable, coaxial cable, fiber-optic cable, and
wireless.
Wireless media carry electromagnetic signals that represent the binary digits of data
communications using radio or microwave frequencies. As a
networking medium, wireless is not restricted to conductors or pathways, as are
copper and fiber media. Wireless media provides the greatest mobility options of
all media.
Ex:
An Ethernet cable is one of the most common forms of network cable used on wired
networks. Ethernet cables connect devices within a local area network, like PCs,
routers, and switches.
Fiber optic cable is a high-speed data transmission medium. It contains tiny glass or
plastic filaments that carry light beams. Digital data is transmitted through the cable via
rapid pulses of light.
ASS 1.2: Identify the network structure and devices according to their types and
specifications
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L.O1.3: Select tools, materials and equipment according to the work to be done
A wire stripper is a small, hand-held device used to strip the electrical insulation from
electric wires.
Coax crimping tool: This crimp tool set allows users to easily attach various types of
RF/coax connectors to the specified cables.
iDVR
An Integrated digital video recorder (DVR) is an electronic device that records video in a
digital format to a disk drive, USB flash drive, SD memory card, SSD or other local or
networked mass storage device.
NVR
A network video recorder (NVR) is a software program that records video in a digital
format to a disk drive, USB flash drive, SD memory card or other mass storage device.
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CAMERA
A camera is a piece of equipment that is used for taking photographs, making films, or
producing television pictures.
An uninterruptible power supply (UPS) is a device that provides electrical power to keep
running devices for at least a short time when the primary power source is lost. It also
provides protection from power surges.
DIGITAL MULTIMETER
A digital multimeter (DMM) is a test tool used to measure two or more electrical values
principally voltage (volts), current (amps) and resistance (ohms). It is a standard
diagnostic tool for technicians in the electrical/electronic industries.
CABLE TESTER
These portable service monitors are one of the most convenient tools that a CCTV
installer can have with him when performing an installation. Professional installers often
refer to these devices as an LCD field monitor or CCTV field monitor.
A flat panel screen that uses the liquid crystal display (LCD) technology and connects
to a computer. Laptops have used LCD screens almost exclusively, and the LCD
monitor is the standard display screen for desktop computers.
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