CCTV. CAMERA EXPLANATION

A CCTV security system is essential for any type of business or public organization. Therefore it’s vital to select the right CCTV camera for the right location and application.

There are lots of CCTV cameras to choose from on the market today, with many different features and options, resulting in a confusing array of various types, styles, and configurations. But which is best for your intended business security application?

Here Are The 8 Different Types Of CCTV Cameras You Should Know About:

1. Dome CCTV Camera

Dome CCTV Cameras are most commonly used for indoor security and surveillance applications. Dome cameras get their name from the dome-shaped housing in which they sit. These housings are designed to make the CCTV cameras unobtrusive… not covert or hidden. Typical applications are retail, where the camera is designed to be unobtrusive, but visible.

The "dome" shape makes it difficult to tell the direction that these cameras are facing, and thus are ideal for deterring criminals. The “bad guys” will know the facility is being watched and customers will feel at ease knowing the facility is being protected. Units that allow the camera to pan/tilt/zoom and spin quickly within the housing are often referred to as “speed domes.”

Speed Dome CCTV cameras give the surveillance operator the ability to move the camera. There are cameras that have automated pan/tilt/zoom functionality where the camera is moving on a timed basis. These are used to cover a wide area with only one camera, or to avoid poor light conditions at certain times of day.

2. Bullet CCTV Camera

Bullet CCTV Cameras have a long, cylindrical, and tapered shape, similar to that of a "rifle bullet", often used in applications that require long distance viewing. The camera is not typically designed to have pan/tilt/zoom control but instead to capture images from a fixed location, pointing at a particular area. 

A bullet CCTV camera is a wall-mount or ceiling-mounted unit that is typically designed for indoor use, but can also be used for some outdoor applications.  Many bullet cameras can also be waterproof by being installed inside protective casings, which protect against dust, dirt, rain, hail and other harmful elements. 

3. C-Mount CCTV Camera

C-mount CCTV cameras have detachable lenses to fit different applications. Standard CCTV camera lenses can only cover distances of between 35 and 40ft, therefore with C-mount CCTV cameras, it is possible to use special lenses, which can cover distances greater than 40ft.

4. Day/Night CCTV Camera

The day/night CCTV cameras have the distinct advantage of operating in both normal and poorly-lit environments. These cameras do not have Infrared illuminators because they can capture clear video images in varying light conditions and in the dark. 

The camera is ideal for outdoor surveillance applications, where Infrared CCTV cameras cannot function optimally. These CCTV cameras are primarily used in outdoor applications and they can have a wide dynamic range to function in glare, direct sunlight, reflections and strong back light 24/7.

5. Infrared/Night Vision CCTV Camera

These night-vision CCTV cameras have the ability to see images in pitch black conditions using Infrared LEDs and are ideal in outside conditions where lighting is poor to zero.

6. Network/IP CCTV Camera

These cameras, both hardwired and wireless, transmit images over the Internet, often compressing the bandwidth so as not to overwhelm the web. IP cameras are easier to install than analog cameras because they do not require a separate cable run or power boost to send images over a longer distance.

7. Wireless CCTV Camera

Not all wireless cameras are IP-based. Some wireless cameras can use alternative modes of wireless transmission. But no matter what the transmission method, the primary benefit to these units is still the same: extreme flexibility in installation. 

8. High-Definition HD CCTV Camera

Ultra high-definition cameras are often relegated to niche markets, such as casinos and banks. These give the operators the ability to zoom in with extreme clarity (to look at a poker player who might have something up their sleeve). 

Beyond this list, there are many other types of CCTV cameras, but most of those are more related to the application in which the unit will be used vs. the type of camera.

Sonitrol Western Canada provides a range of CCTV cameras, which we select to do the right job in the right location. We offer full service CCTV design, installation, support, monitoring services, and integration with audio and access management security systems, including all key CCTV camera system types, components, accessories and concepts such as:

• Sonitrol will install the right CCTV camera for your business (including IP, infrared, low-light, HD, verified, wireless, day/night, c-mount, bullet, dome, waterproof)
• 24/7 CCTV camera monitoring at our remote monitoring station
• DVRs (digital video recorders)
• CCTV camera towers and columns
• CCTV telemetry systems
• Deterrent CCTV systems
• Covert CCTV systems
• Motion detection systems
• Integrated audio / CCTV systems
• Video Analytics/Predictive software
• CCTV camera lenses
• CCTV monitors
• CCTV multiplexors
• CCTV illumination
• CCTV switchers
• Fibre optic CCTV transmission
• Networked CCTV transmission (IP CCTV transmission)
• Wireless CCTV camera systems
• Software systems for CCTV camera control, CCTV management & CCTV diagnostics

Sonitrol Western Canada can provide CCTV video surveillance support for interior and exterior video surveillance solutions that range in size from centrally monitored, total corporate systems (fully-networked with dedicated fibre optic backbones) to PC-controlled, IP-based, stand-alone remote access verifiers.

Whether stand-alone or part of an integrated security system, CCTV cameras can be called upon to perform a number of functions for the organizations which use them, detection, deterrence, reassurance, evidence, access control and facility management. Utilizing our in-house security consultants, we have embraced verified security CCTV technologies, video transmission technology and network/IP communications as part of our core CCTV service; so ensuring we can meet customer requirements to provide CCTV system installation and CCTV system support for our high reliability, multi-functional, tailor-made CCTV solutions.

About Sonitrol Western Canada:

We're so confident in our technology and responsive service, that no one else in the industry can match our guarantee.  Our unique verified audio and CCTV video business security solutions enable our operators to hear and see what is happening in your business before the criminals gain entry!!  We verify the actual source of the alarm, and we get the police to attend the scene immediately.  FOR A FREE SECURITY AUDIT, click here, or call 1-866-766-4876.

We are a security company with over 150 offices across North America. Sonitrol Western Canada services clients in:

• BritishColumbia
• Alberta
• Saskatchewan
• Victoria, 
• Vancouver
• Edmonton
• Calgary
• Saskatoon

Sonitrol Western Canada, with its Verified Electronic Security Systems, is committed to providing customers with the most comprehensive security protection.  Cooperation in the elimination of false alarms is not only beneficial to the system’s user, but results in better protection of the entire community by allowing law enforcement to use their resources as efficiently as possible.

COMPUTER MAINTAIN (REPAIR HARDWARE)

POST (POWER ON SELF TEST)
Na        @lucas.
Ushwai kujiuliza kwanini computer haiwaki moja kwa moja mbaka ubofye f1? Au kwanini computer haiwaki bali inakulete  beep code?
BIOS – Is the basic of input/output is the small piece of software that control the basic of hardware functionallty of computer and it’s saved in an EPROM CHIP Of the motherbord.
The system bios program start by invoking a special program (stored on a Rom chip) Rom chip imeifadhi firmware ambayo imebaniwa katika Rom kwa kirefu rom ni “read only memory” Ambayo ime contains  basic instructions  ni kitu gani kinaitajika baada ya computer kuiwasha.
Firmware –Zinatoa basic code ili computer kuweza kuwaka hizi zinatengenezwa programmer ambao wanasoma programming language
Vitu vifatavyo vinafatwa kabla ya computer kuwaka ambavyo
POST-ni kirefu cha “power on self test” inagalia computer hardware za ndani,Kuhakikisha kuwa hakuna kosa lolote/ubovu wotete katika hardware za ndani kabla ya kufunguka kwa “Os” kirefu chake ni open stystem. Endapo computer itafaulu katika post computer inaweza kutoa single beep (same computer zinaweza kutoa beep twice) kuiyanzisha na kurudia tena kufunguka. However kama computer itafeli katika katika power on self test(post) inaweza isilete beeps au ikatengeza beep code  na ikamueleza mtumiaji kwa kupitia hizo  beeps code kuwa tatizo lipo sehemu gani/Katika hardware gani ya ndani ya computer.  Beeps code ni nini mlio flani hivi inaweza ikaleta milio mara tatu mfano titiiiii ! tiiiiii!  Tiiiii! au mara tano hizi beeps code zinatolewa kuna spika  ya ndani ipo katika motherboard ,hii  kama nilivyopata kusema hapo juu inaweza kulia hizo beeps/Kutengenezwa  hizo beeps  code kutokana na tatizo katika hardware flani yenye Tatizo. N.b beeps code zinatofatia so ntaleta jinsi gani utakavyo skia hizo beeps code na kupata kufahamu tatizo lilipowapi . Siyo kila pc inaweza kuleletea hizo beeps code kwakutumia spika iliyopo katika motherboard bali nyengine zinaweza kukuonyesha hizo beeps code kwa kuleta taa zilizopo hapo katika computer yako,Kwa mfano paaap unaiwasha computer yako na ikafeli katika post inaweza hizo taa zilizopo hapo katika kitufe cha kuwashia au popote zilipowekwa/kutokana na PC zinatofautiana,Iinaweza kukuonyesha kwa kukuendiketi yani kuwaka na kuzima ! kuwaka na kuzima! Kutoka na hizo beeps code za tatizo katika hardware za ndani,kama nilivyopata kusema hapo juu beeps code zinatofautiana Kwa mfano labla tatizo lipo katika RAM SLOT inaweza ikawa beeps code ni tano ili mtumiaji apate kuelewa aaah! Kumbe tatizo lipo katika “ram slot” .
Tip: Hakikisha kama utawasha computer yako na hakuna kitu chochote kilichotekea( hakuna mwanga hakuna sauti na hakuna uzungukaji wa feni n.k )The computer has a power related issue.

 Computer programming "PHP language"

PHP 5 Variables

---

Variables are "containers" for storing information.

---

Creating (Declaring) PHP Variables

In PHP, a variable starts with the $ sign, followed by the name of the variable:

Example

<?php
$txt = "Hello world!";
$x = 5;
$y = 10.5;
?>

After the execution of the statements above, the variable $txt will hold the value Hello world!, the variable $x will hold the value 5, and the variable $y will hold the value 10.5.

Note: When you assign a text value to a variable, put quotes around the value.

Note: Unlike other programming languages, PHP has no command for declaring a variable. It is created the moment you first assign a value to it.

Think of variables as containers for storing data.

---

PHP Variables

A variable can have a short name (like x and y) or a more descriptive name (age, carname, total_volume).

Rules for PHP variables:

• A variable starts with the $ sign, followed by the name of the variable
• A variable name must start with a letter or the underscore character
• A variable name cannot start with a number
• A variable name can only contain alpha-numeric characters and underscores (A-z, 0-9, and _ )
• Variable names are case-sensitive ($age and $AGE are two different variables)

Remember that PHP variable names are case-sensitive!

---

Output Variables

The PHP echo statement is often used to output data to the screen.

The following example will show how to output text and a variable:

Example

<?php
$txt = "Omega.com";
echo "I love $txt!";
?>

The following example will produce the same output as the example above:

Example

<?php
$txt = "Omega.com";
echo "I love " . $txt . "!";
?>

The following example will output the sum of two variables:

Example

<?php
$x = 5;
$y = 4;
echo $x + $y;
?>

Note: You will learn more about the echo statement and how to output data to the screen in the next chapter.

---

PHP is a Loosely Typed Language

In the example above, notice that we did not have to tell PHP which data type the variable is.

PHP automatically converts the variable to the correct data type, depending on its value.

In other languages such as C, C++, and Java, the programmer must declare the name and type of the variable before using it.

---

PHP Variables Scope

In PHP, variables can be declared anywhere in the script.

The scope of a variable is the part of the script where the variable can be referenced/used.

PHP has three different variable scopes:

• local
• global
• static

---

Global and Local Scope

A variable declared outside a function has a GLOBAL SCOPE and can only be accessed outside a function:

Example

<?php
$x = 5; // global scope

function myTest() {
    // using x inside this function will generate an error
    echo "<p>Variable x inside function is: $x</p>";
}
myTest();

echo "<p>Variable x outside function is: $x</p>";
?>

A variable declared within a function has a LOCAL SCOPE and can only be accessed within that function:

Example

<?php
function myTest() {
    $x = 5; // local scope
    echo "<p>Variable x inside function is: $x</p>";
}
myTest();

// using x outside the function will generate an error
echo "<p>Variable x outside function is: $x</p>";
?>

You can have local variables with the same name in different functions, because local variables are only recognized by the function in which they are declared.

---

PHP The global Keyword

The global keyword is used to access a global variable from within a function.

To do this, use the global keyword before the variables (inside the function):

Example

<?php
$x = 5;
$y = 10;

function myTest() {
    global $x, $y;
    $y = $x + $y;
}

myTest();
echo $y; // outputs 15
?>

PHP also stores all global variables in an array called $GLOBALS[index]. The index holds the name of the variable. This array is also accessible from within functions and can be used to update global variables directly.

The example above can be rewritten like this:

Example

<?php
$x = 5;
$y = 10;

function myTest() {
    $GLOBALS['y'] = $GLOBALS['x'] + $GLOBALS['y'];
}

myTest();
echo $y; // outputs 15
?>

---

PHP The static Keyword

Normally, when a function is completed/executed, all of its variables are deleted. However, sometimes we want a local variable NOT to be deleted. We need it for a further job.

To do this, use the static keyword when you first declare the variable:

Example

<?php
function myTest() {
    static $x = 0;
    echo $x;
    $x++;
}

myTest();
myTest();
myTest();
?>

Then, each time the function is called, that variable will still have the information it contained from the last time the function was called.

Note: The variable is still local to the function.

Top 100 Networking Interview Questions & Answers

1) What does 10Base-T mean?
The 10 refers to the data transfer rate, in this case is 10Mbps. The word Base refers to base band, as oppose to broad band. T means twisted pair, which is the cable used for that network.

2) What is a private IP address?
Private IP addresses are assigned for use on intranets. These addresses are used for internal networks and are not routable on external public networks. These ensures that no conflicts are present among internal networks while at the same time the same range of private IP addresses are reusable for multiple intranets since they do not “see” each other.

3) What is NOS?
NOS, or Network Operating System, is specialized software whose main task is to provide network connectivity to a computer in order for it to be able to communicate with other computers and connected devices.

4) What is DoS?
DoS, or Denial-of-Service attack, is an attempt to prevent users from being able to access the internet or any other network services. Such attacks may come in different forms and are done by a group of perpetuators. One common method of doing this is to overload the system server so it cannot anymore process legitimate traffic and will be forced to reset.

5) What is OSI and what role does it play in computer networks?
OSI (Open Systems Interconnect) serves as a reference model for data communication. It is made up of 7 layers, with each layer defining a particular aspect on how network devices connect and communicate with one another. One layer may deal with the physical media used, while another layer dictates how data is actually transmitted across the network.

6) What is the purpose of cables being shielded and having twisted pairs?
The main purpose of this is to prevent crosstalk. Crosstalks are electromagnetic interferences or noise that can affect data being transmitted across cables.

7) What is the advantage of address sharing?
By using address translation instead of routing, address sharing provides an inherent security benefit. That’s because host PCs on the Internet can only see the public IP address of the external interface on the computer that provides address translation and not the private IP addresses on the internal network.

8) What are MAC addresses?
MAC, or Media Access Control, uniquely identifies a device on the network. It is also known as physical address or Ethernet address. A MAC address is made up of 6-byte parts.

9) What is the equivalent layer or layers of the TCP/IP Application layer in terms of OSI reference model?
The TCP/IP Application layer actually has three counterparts on the OSI model: the Session layer, Presentation Layer and Application Layer.

10) How can you identify the IP class of a given IP address?
By looking at the first octet of any given IP address, you can identify whether it’s Class A, B or C. If the first octet begins with a 0 bit, that address is Class A. If it begins with bits 10 then that address is a Class B address. If it begins with 110, then it’s a Class C network.

11) What is the main purpose of OSPF?
OSPF, or Open Shortest Path First, is a link-state routing protocol that uses routing tables to determine the best possible path for data exchange.

12) What are firewalls?
Firewalls serve to protect an internal network from external attacks. These external threats can be hackers who want to steal data or computer viruses that can wipe out data in an instant. It also prevents other users from external networks from gaining access to the private network.

13) Describe star topology
Star topology consists of a central hub that connects to nodes. This is one of the easiest to setup and maintain.

14) What are gateways?
Gateways provide connectivity between two or more network segments. It is usually a computer that runs the gateway software and provides translation services. This translation is a key in allowing different systems to communicate on the network.

15) What is the disadvantage of a star topology?
One major disadvantage of star topology is that once the central hub or switch get damaged, the entire network becomes unusable.

16) What is SLIP?
SLIP, or Serial Line Interface Protocol, is actually an old protocol developed during the early UNIX days. This is one of the protocols that are used for remote access.

17) Give some examples of private network addresses.
10.0.0.0 with a subnet mask of 255.0.0.0

172.16.0.0 with subnet mask of 255.240.0.0

192.168.0.0 with subnet mask of 255.255.0.0

18) What is tracert?
Tracert is a Windows utility program that can used to trace the route taken by data from the router to the destination network. It also shows the number of hops taken during the entire transmission route.

19) What are the functions of a network administrator?
A network administrator has many responsibilities that can be summarize into 3 key functions: installation of a network, configuration of network settings, and maintenance/troubleshooting of networks.

20) Describe at one disadvantage of a peer to peer network.
When you are accessing the resources that are shared by one of the workstations on the network, that workstation takes a performance hit.

21) What is Hybrid Network?
A hybrid network is a network setup that makes use of both client-server and peer-to-peer architecture.

22) What is DHCP?
DHCP is short for Dynamic Host Configuration Protocol. Its main task is to automatically assign an IP address to devices across the network. It first checks for the next available address not yet taken by any device, then assigns this to a network device.

23) What is the main job of the ARP?
The main task of ARP or Address Resolution Protocol is to map a known IP address to a MAC layer address.

24) What is TCP/IP?
TCP/IP is short for Transmission Control Protocol / Internet Protocol. This is a set of protocol layers that is designed to make data exchange possible on different types of computer networks, also known as heterogeneous network.

25) How can you manage a network using a router?
Routers have built in console that lets you configure different settings, like security and data logging. You can assign restrictions to computers, such as what resources it is allowed access, or what particular time of the day they can browse the internet. You can even put restrictions on what websites are not viewable across the entire network.

Top 100 Networking Interview Questions & Answers

1) What is a Link?
A link refers to the connectivity between two devices. It includes the type of cables and protocols used in order for one device to be able to communicate with the other.

2) What are the layers of the OSI reference model?
There are 7 OSI layers: Physical Layer, Data Link Layer, Network Layer, Transport Layer, Session Layer, Presentation Layer and Application Layer.

3) What is backbone network?
A backbone network is a centralized infrastructure that is designed to distribute different routes and data to various networks. It also handles management of bandwidth and various channels.

4) What is a LAN?
LAN is short for Local Area Network. It refers to the connection between computers and other network devices that are located within a small physical location.

5) What is a node?
A node refers to a point or joint where a connection takes place. It can be computer or device that is part of a network. Two or more nodes are needed in order to form a network connection.

6) What are routers?
Routers can connect two or more network segments. These are intelligent network devices that store information in its routing table such as paths, hops and bottlenecks. With this info, they are able to determine the best path for data transfer. Routers operate at the OSI Network Layer.

7) What is point to point link?
It refers to a direct connection between two computers on a network. A point to point connection does not need any other network devices other than connecting a cable to the NIC cards of both computers.

8) What is anonymous FTP?
Anonymous FTP is a way of granting user access to files in public servers. Users that are allowed access to data in these servers do not need to identify themselves, but instead log in as an anonymous guest.

9) What is subnet mask?
A subnet mask is combined with an IP address in order to identify two parts: the extended network address and the host address. Like an IP address, a subnet mask is made up of 32 bits.

10) What is the maximum length allowed for a UTP cable?
A single segment of UTP cable has an allowable length of 90 to 100 meters. This limitation can be overcome by using repeaters and switches.

11) What is data encapsulation?
Data encapsulation is the process of breaking down information into smaller manageable chunks before it is transmitted across the network. It is also in this process that the source and destination addresses are attached into the headers, along with parity checks.

12) Describe Network Topology
Network Topology refers to the layout of a computer network. It shows how devices and cables are physically laid out, as well as how they connect to one another.

13) What is VPN?
VPN means Virtual Private Network, a technology that allows a secure tunnel to be created across a network such as the Internet. For example, VPNs allow you to establish a secure dial-up connection to a remote server.

14) Briefly describe NAT.
NAT is Network Address Translation. This is a protocol that provides a way for multiple computers on a common network to share single connection to the Internet.

15) What is the job of the Network Layer under the OSI reference model?
The Network layer is responsible for data routing, packet switching and control of network congestion. Routers operate under this layer.

16) How does a network topology affect your decision in setting up a network?

Network topology dictates what media you must use to interconnect devices. It also serves as basis on what materials, connector and terminations that is applicable for the setup.

17) What is RIP?
RIP, short for Routing Information Protocol is used by routers to send data from one network to another. It efficiently manages routing data by broadcasting its routing table to all other routers within the network. It determines the network distance in units of hops.

18) What are different ways of securing a computer network?
There are several ways to do this. Install reliable and updated anti-virus program on all computers. Make sure firewalls are setup and configured properly. User authentication will also help a lot. All of these combined would make a highly secured network.

19) What is NIC?
NIC is short for Network Interface Card. This is a peripheral card that is attached to a PC in order to connect to a network. Every NIC has its own MAC address that identifies the PC on the network.

20) What is WAN?
WAN stands for Wide Area Network. It is an interconnection of computers and devices that are geographically dispersed. It connects networks that are located in different regions and countries.

21) What is the importance of the OSI Physical Layer?
The physical layer does the conversion from data bits to electrical signal, and vice versa. This is where network devices and cable types are considered and setup.

22) How many layers are there under TCP/IP?
There are four layers: the Network Layer, Internet Layer, Transport Layer and Application Layer.

23) What are proxy servers and how do they protect computer networks?
Proxy servers primarily prevent external users who identifying the IP addresses of an internal network. Without knowledge of the correct IP address, even the physical location of the network cannot be identified. Proxy servers can make a network virtually invisible to external users.

24) What is the function of the OSI Session Layer?
This layer provides the protocols and means for two devices on the network to communicate with each other by holding a session. This includes setting up the session, managing information exchange during the session, and tear-down process upon termination of the session.

25) What is the importance of implementing a Fault Tolerance System? Are there limitations?
A fault tolerance system ensures continuous data availability. This is done by eliminating a single point of failure. However, this type of system would not be able to protect data in some cases, such as in accidental deletions.

What are RFCs

What are RFCs

A RFC (Request for Comments) is a pure technical document published by the Internet Engineering Task Force (IETF). Request for Comments (RFCs) are mainly used to develop a "standard" network protocol, a function of a network protocol or any feature which is related with network communication.

Some RFCs are informational and others are published Internet standards. The final version of the RFC becomes the standard and is published with a number. No further comments or changes are permitted for the final version. Changes are permitted only via subsequent RFCs that supersede the previous RFCs.

At the early stages of network communication, each vendor had their own proprietary network communication protocols. Different network protocols for the same purpose were a serious problem in heterogeneous network environments, consisting of devices and Operating Systems from different vendors.

"Standard" network protocols are not considered as proprietary. Any vendor can develop application software or drivers based on defined RFC standard. Hence RFC provides a strong base for cross platform network communication.

All the standard network protocols (like, HTTP, FTP, SMTP, TCP, UDP, IP etc) are defined as RFCs. Individuals may join the IETF working groups to help draft and develop networking standards or network protocols.
More than 7000 RFCs are available now. 

Difference between Baseband and Broadband

Difference between Baseband and Broadband

In Baseband, data is sent as digital signals through the media as a single channel that uses the entire bandwidth of the media. Baseband communication is bi-directional, which means that the same channel can be used to send and receive signals. In Baseband, frequency-division multiplexing is not possible. (Multiplexing (short muxing) is a process where multiple analog message signals or digital data streams are combined into one signal over a shared medium.) 

Broadband sends information in the form of an analog signal. Each transmission is assigned to a portion of the bandwidth, hence multiple transmissions are possible at the same time. Broadband communication is unidirectional, so in order to send and receive, two pathways are needed. This can be accomplished either by assigning a frequency for sending and assigning a frequency for receiving along the same cable or by using two cables, one for sending and one for receiving. In broadband frequency-division multiplexing is possible.