Transmission of Camera Video Signals by Cable

A CCTV cable is basically an RG59 coaxial cable that is used to transmit a video signal between your security camera and the DVR (Digital Video Recorder). The RG59 is attached to both the security camera and DVR via a male BNC connector. The female BNC connection on the back of the DVR and security camera allows for these components to attach. The BNC connection creates a locking mechanism that creates a long lasting solid connection.

 

This is not meant to be a textbook on transmission but is intended to remove some of the mystery associated with various methods of transmission. Many approximations and simplifications have been used in writing this guide. This is to make the subject more understandable to those people not familiar with the theories. For general application in the design of CCTV systems it should be more than adequate and at least point the way to the main questions that must be addressed. The manufacturers of transmission equipment will usually be only too keen to help in final design.

 This connection diagram illustrates the many methods of getting a picture from a camera to a monitor. The choice will often be dictated by circumstances on the location of cameras and controls. Often there will be more than one option for types of transmission. In these cases there will possibly be trade offs between quality and security of signal against cost. This diagram could now include transmission by IP networks. 

General Principles

 

Video Signal

The essential components of the video signal are covered in Chapters two and three. Certain aspects that are related to the effective transmission of those signals are repeated in this chapter where it is necessary to save continuous cross-reference.

Synchronizing

The video signal from a TV camera has to provide a variety of information at the monitor for a correct TV picture to be displayed. This information can be divided into: Synchronizing pulses that tell the monitor when to start a line and a field; video information that tells the monitor how bright a particular point in the picture should be; chrominance that tells the monitor what colours a particular part of the picture should be (colour cameras only).

Bandwidth

The composite video output from the average CCTV camera covers a bandwidth ranging from 25Hz to 5MHz. The upper frequency is primarily determined by the resolution of the camera and whether it is monochrome or colour. For every 100 lines of resolution, a bandwidth of 1MHz approximately is required. Therefore, a camera with 600 lines resolution gives out a video signal with a bandwidth of approximately 6MHz. This principle applies to both colour and monochrome cameras. However, colour cameras also have to produce a colour signal (chrominance), as well as a monochrome output (luminance). The chrominance signal is modulated on a 4.43MHz carrier wave in the PAL system therefore a colour signal, regardless of definition, has a bandwidth of at least 5MHz.

Requirements to Produce A Good Quality Picture

From the above it will be obvious that to produce a good quality picture on a monitor, the video signal must be applied to the monitor with little or no distortion of any of its elements, i.e. the time relationship of the various signals and amplitude of these signals. However in CCTV systems, the camera has to be connected to a monitor by a cable or another means, such as Fibre Optic or microwave link. This interconnection requires special equipment to interface the video signal to the transmission medium. In cable transmission, special amplifiers may be required to compensate for the cable losses that are frequency dependent.

Cable Transmission

All cables, no matter what their length or quality, cause attenuation when used for the transmission of video signals, the main problem being related to the wide bandwidth requirements of a video signal. All cables produce a loss of signal that is dependent primarily on the frequency, the higher the frequency, the higher the loss. This means that as a video signal travels along a cable it loses its high frequency components faster than its low frequency components. The result of this is a loss of the fine detail (definition) in the picture.

The human eye is very tolerant of errors of this type; a significant loss of detail is not usually objectionable unless the loss is very large. This is fortunate, as the losses of the high frequency components are very high on the types of cables usually used in CCTV systems. For instance, using the common coaxial cables URM70 or RG59, 50% of the signal at 5MHz is lost in 200 meters of cable. To compensate for these losses, special amplifiers may be used. These provide the ability to amplify selectively the high frequency components of the video signal to overcome the cable losses.

Cable Types

There are two main types of cable used for transmitting video signals, which are: Unbalanced (coaxial) and balanced (twisted pair). The construction of each is shown in diagrams 15.2 and 15.3. An unbalanced signal is one in which the signal level is a voltage referenced to ground. For instance, a video signal from the camera is between 0.3 and 1.0 volts above zero (ground level). The shield is the ground level.

A balanced signal is a video signal that has been converted for transmission along a medium other than coaxial cable. Here the signal voltage is the difference between the voltages in each conductor.

External interference is picked up by all types of cable. Rejection of this interference is effected in different ways. Coaxial cable relies on the centre conductor being well screened by the outer copper braid. There are many types of coaxial cable and care should be taken to select one with a 95% braid. In the case of a twisted pair cable, interference is picked up by both conductors in the same direction equally. The video signal is traveling in opposite directions in the two conductors. The interference can then be balanced out by using the correct type of amplifier. This only responds to the signal difference in the two conductors and is known as a differential amplifier.

Unbalanced (Coaxial) Cables

This type of cable is made in many different types of impedance. In this case impedance is measured between the inner conductor and the outer sheath. 75-Ohm impedance cable is the standard used in CCTV systems. Most video equipment is designed to operate at this impedance. Coaxial cables with an impedance of 75 Ohms are available in many different mechanical formats, including single wire armored and irradiated PVC sheathed cable for direct burial. The cables available range in performance from relatively poor to excellent. Performance is normally measured in high frequency loss per 100 meters. The lower this loss figure, the less the distortion to the video signal. Therefore, higher quality cables should be used when transmitting the signal over long distances.

Another factor that should be considered carefully when selecting coaxial cables is the quality of the cable screen. This, as its name suggests, provides protection from interference for the center core, as once interference enters the cable it is almost impossible to remove. 

Unbalanced Cable

Balanced (Twisted Pair) Cables

In a twisted pair each pair of cables is twisted with a slow twist of about one to two twists per meter. These cables are made in many different types of impedance, 100 to 150 Ohms being the most common. Balanced cables have been used for many years in the largest cable networks in the world. Where the circumstances demand, these have advantages over coaxial cables of similar size. Twisted pair cables are frequently used where there would be an unacceptable loss due to a long run of coaxial cable.

The main advantages are:

1. The ability to reject unwanted interference.

2. Lower losses at high frequencies per unit length.

3. Smaller size.

4. Availability of multipair cables.

5. Lower cost.

Balanced Cable

The advantages must be considered in relation to the cost of the equipment required for this type of transmission. A launch amplifier to convert the video signal is needed at the camera end and an equalizing amplifier to reconstruct the signal at the control end.

Impedance

It is extremely important that the impedance of the signal source, cable, and load are all equal. Any mismatch in these will produce unpleasant and unacceptable effects in the displayed picture. These effects can include the production of ghost images and ringing on sharp edges, also the loss or increase in a discrete section of the frequency band within the video signal.

The impedance of a cable is primarily determined by its physical construction, the thickness of the conductors and the spacing between them being the most important factors. The materials used as insulators within the cable also affect this characteristic. Although the signal currents are very low, the sizes of the conductors within the cable are very important. The higher frequency components of the video signal travel only in the surface layer of the conductors.

Transmission Impedance

For maximum power transfer, the load, cable and source impedance must be equal. If there is any mismatch, some of the signal will not be absorbed by the load. Instead, it will be reflected back along the cable to produce ghost image.

Tips and hints while installing co-axial cable.

1. Use solid core co-axial cable only, not stranded cable. The solid core must have a copper core with copper shield
2. Avoid high voltage cable. A good rule to follow is: for every 100 volts there should be a separation of 1ft between the video cable and power cable.
3. While cabling, avoid areas like electrical equipment or transmitter rooms etc., where EMI interference is expected. This can create all types of interference to the video picture. Co-axial cable is very easily prone to EMI.
4. Minimize cable breaks - Every extra connection in the cable can deteriorate the quality of the video signal. If unavoidable, make sure the insulation is good; otherwise over time the exposed cable can touch the ground causing ground loop currents. It may be difficult or expensive to fix such problems in the future.
5. Avoid sharp bends, which affects the cable impedance causing picture reflection and distortion. This is especially true while getting all the cable into the CCTV monitor rack.
6. Poor BNC connections is the major cause of poor picture quality. Also BNC connectors should be replaced every couple of years and should be part of the system maintenance program.
7. Use metal conduits for high security applications.
8. Use heavy-duty cable for outdoor applications providing better protection against the elements.

Before choosing the CCTV cable for your application put some thought into the location of your power supply and your video recording device to determine if using a Siamese CCTV Cable type or individual cables (separate RG59 and 18/2) best suit your installation. If all your equipment is in one central location then using a Siamese CCTV Cable may provide you with the most professional and cleanest installation. We hope your surveillance system installation is a complete success! Good Luck!

CCTV Data Protection Act

CCTV Data Protection Act

Since the 24th October 2001 it has been a criminal offense to use an unregistered CCTV system to record people in a public or private place unless it meets certain criteria.
The introduction of the Data Protection Act 1998 and other related legislation has had far reaching consequences for those who own, manage or operate CCTV systems. Every aspect of this new legislation impacts upon your use of CCTV.

The Code of Practice contains 62 legally enforceable 'Standards' that must be met to ensure compliance with the Data Protection Act 1998. The Commissioner includes a further 30 points of good practice, which together with the standards, are designed to build and maintain public confidence in CCTV systems and to ensure that they operate within the law.
The Data Protection Act (DPA) 1998 came into force on March 1st 2000 and the Information Commissioner has issued a Code of Practice for CCTV systems. This Code was updated on July 14th 2000 and again in January 2008 and is available from us as part of our Data Protection Information Pack.

You will find at The Data Protection Act and CCTV our own interpretation and summary of the requirements of the act. This however still leaves a number of questions unanswered so we have prepared a Data Protection Information Pack for visitors to this site. This should answer most of the questions that you may have concerning The Data Protection Act and CCTV as well as providing an extensive checklist enabling you to ensure that your organization is fully complying with the requirements of the legislation.

Information Pack contains the following:
1. DPA Code of Practice from the Information Commissioner's Office. This explains what the law requires of you if you have a CCTV System.
2. DPA Self Assessment Pack providing further details on the law and a simple checklist for you to ensure that your organization is complying with the DPA.
3. DPA Catalogue of items that you may need in order to comply with the requirements of the DPA. e.g. Signs, Download CD's or DVD's, necessary forms, etc.
4. An order form should you wish to order any of the catalogue items.

Ensuring that an organization’s CCTV system is fully compliant with the Data Protection Act can often involve weeks of work. Very often this time is spent reinventing the wheel as VeriFi can conduct a full professional assessment of your system and provide full documentation and comprehensive advice on where your system meets or fails to meet current legislation and official guidelines. However, a VeriFi Assessment goes much further than this in that it sets up a complete framework on which to base your CCTV management.

The VeriFi solution
VeriFi can supply an Independent Consultant to conduct a CCTV Compliance Assessment, provide full documentation and comprehensive advice on where your system meets or fails to meet current legislation and official guidelines. However, a VeriFi Assessment goes much further than this in that it sets up a complete framework on which to base your CCTV management. The following are all covered by the VeriFi service.
Information Commissioners Office
Almost all CCTV systems must be registered with the Information Commissioners Office. VeriFi will inform you of shortcomings in regard to your ICO notification.
Policy Document
You will require a statement itemising how your CCTV system is to be managed and stating who is fulfilling the roles of Data Controller and Data Processor.
Operational Requirement
According to the Home Office an Operational Requirement should be drawn up before any CCTV system is specified and form the basis for the design of the system. This document then provides evidence for the relevance of your system in respect to the DPA. VeriFi will reverse engineer an Operational Requirement and advise you of any shortfalls or redundancy within the system.
Privacy
It is a serious infringement of the DPA for your CCTV system to invade the privacy of other people and their property. VeriFi will inform you of any such breaches and advise on the steps that should be taken to correct the situation.
CCTV Signage
You must ensure that you inform people before, or as, they enter an area where there is CCTV surveillance. As you can only use your CCTV system for the purposes which are stated on the signage it is important that the correct wording is used. VeriFi advise you on the correct wording for your organization and can arrange the purchase of all necessary signage.
Annual CCTV Audit
To comply with the Information Commissioners Office CCTV Policy Document VeriFi undertakes a manual audit on behalf of its clients and provides them with comprehensive advice on any shortcomings. This is designed to ensure that your staff for contractors will effectively manage your CCTV on a continuing basis.
Management Documentation
Clients of VeriFi receive, free of charge, a comprehensive package of the necessary documentation required under the DPA as well is training in its use.
Recording Media
To help ensure that images are usable in a court of law it is essential that any CDs or DVDs are Data Compliant (media purchased from retail outlets will not be suitable). Also supplied free of charge to VeriFi clients are the necessary compliant CD's/DVDs. Should you require more documentation or recording media this can be ordered online and is normally supplied on the next working day.
Right of Access Management
Under the DPA members of the public have a right to access of their recorded images. The VeriFi Application Form that is supplied as part of this service includes a statement of the individual's rights and how Subject Access Requests are managed. This service is designed to ensure full legal compliance.
Public Information
As you must provide for the public a statement of how you manage and operate your CCTV this can be provided to VeriFi clients in either an online or paper format.
Staff Awareness
If you have not made your workforce fully aware of the purpose of the system and how it may apply to them video evidence may be ruled inadmissible. VeriFi clients receive as part of the package, a specific sign for display in staff areas.
Public Complaints Procedure
As it is rare to receive a complaint from the public with regard to the management of CCTV companies normally have no complaints procedure put in place. Where VeriFi manage enquiries on your behalf this includes complaints logging and resolution.
Security of Images
VeriFi will provide an audit of the method you use to secure recorded images. This will include, logging of those people allowed access, the method of access & control of images taken from the system and the tracking any hard disk drives that have been removed from the site.

Other Services:
Although not part of the above Compliance Assessment, the Following Services Are Also Available from VeriFi:
Discreet Evidence Download Service
It is sometimes necessary that evidence be downloaded from the system by someone who is independent from the day-to-day management. A reliable and effective service can be provided by VeriFi should such an event to occur.
Professional Evidence Editing
Where substantial amounts of irrelevant information are downloaded the result is often a noble long and complicated presentation of the facts. To avoid this VeriFi can offer a professional evidence editing service.

The police(Globally) say that 80% of CCTV evidence is inadmissible in court. Causes of such failures include inadequate documentation, lack of audit trail and incorrect recording of evidence.
We recommend that you ensure that you are fully compliant with the DPA as having spent thousands of currency on the installation of a CCTV system it is indefensible to then have the evidence rendered unusable by the relatively small lack of investment in procedural items.
Almost all CCTV systems are required by law to register under the Data Protection Act with the Information Commissioner's Office as well as having, as a minimum, the following items:
1. A Small System Checklist. We supply this free of charge with our Management & Download Pack below.
2. When recording a Compliant CD's or DVD's for recording incidents as well as the necessary forms that you need to log system maintenance, the passing on of evidence to the Police or a third party and other items that may require an audit trail in the event of recordings being required as evidence.
3. The Correct Signage. This may need to include your organization’s name and contact details.

Checklist for users of limited CCTV systems monitoring small retail and business premises

This CCTV system and the images produced by it are controlled by ………………….. who is responsible for how the system is used and for notifying the Information Commissioner about the CCTV system and its purpose (which is a legal requirement of the Data Protection Act 1998).

We (……) have considered the need for using CCTV and have decided it is required for the prevention and detection of crime and for protecting the safety of customers. It will not be used for other purposes. We conduct an annual review of our use of CCTV.

	Checked (Date)	By	Date of next review
Notification has been submitted to the Information Commissioner and the next renewal date recorded.
There is a named individual who is responsible for the operation of the system.
A system has been chosen which produces clear images which the law enforcement bodies (usually the police) can use to investigate crime and these can easily be taken from the system when required.
Cameras have been sited so that they provide clear images.
Cameras have been positioned to avoid capturing the images of persons not visiting the premises.
There are visible signs showing that CCTV is in operation. Where it is not obvious who is responsible for the system contact details are displayed on the sign(s).
Images from this CCTV system are securely stored, where only a limited number of authorised persons may have access to them.
The recorded images will only be retained long enough for any incident to come to light (e.g. for a theft to be noticed) and the incident to be investigated.
Except for law enforcement bodies, images will not be provided to third parties.
The organisation knows how to respond to individuals making requests for copies of their own images. If unsure the controller knows to seek advice from the Information Commissioner as soon as such a request is made.
Regular checks are carried out to ensure that the system is working properly and produces high quality images.

Please keep this checklist in a safe place until the date of the next review.

Monitoring your workforce

When you install CCTV in a workplace, such as a shop, it is likely to capture pictures of workers, even if they are not the main subject of surveillance. If the purpose of the CCTV is solely to prevent and detect crime, then you should not use it for monitoring the amount of work done or compliance with company procedures.

• Have the cameras been installed so they are not directed specifically to capture images of workers?
• Are the recorded images viewed only when there is suspected criminal activity, and not just for routine monitoring of workers? Cameras installed for preventing and detecting crime should not be used for non-criminal matters.
• Are images of workers used only if you see something you cannot be expected to ignore, such as criminal activity, gross misconduct, or behaviour which puts others at risk?
• If these images are used in disciplinary proceedings, is the footage retained so that the worker can see it and respond? A still image is unlikely to be enough.

In some cases, it may be appropriate to install CCTV specifically for workforce monitoring. You should go through the decision making process in section 4 of this code and consider whether it is justified. In particular, consider whether better training or greater supervision would be a more appropriate solution.

Example: You suspect that your workers are stealing goods from the store room. It would be appropriate to install CCTV in this room, as it will not involve continuous or intrusive monitoring and is proportionate to the problem.

Example: You suspect that your workers are making mobile phone calls during working hours, against company policy, and you consider installing CCTV cameras on their desks to monitor them throughout the day. This would be intrusive and disproportionate. Continuous monitoring should only be used in very exceptional circumstances, for example where hazardous substances are used and failure to follow procedures would pose a serious risk to life.

• Is CCTV limited to areas which workers would not expect to be private? CCTV should not be used in toilet areas or private offices.
• Are workers made aware that the CCTV is for staff monitoring and how it will be used? How are visitors informed that CCTV is in operation?
• If CCTV is used to enforce internal policies, are workers fully aware of these policies and have they had sufficient training?
• Do you have procedures to deal appropriately with subject access requests from workers?

Workers should normally be aware that they are being monitored, but in exceptional circumstances, covert monitoring may be used as part of a specific investigation. Covert monitoring is where video or audio recording equipment is used, and those being monitored are unaware that this is taking place. Before approving covert monitoring, you should ask yourself:

• Is this an exceptional circumstance, and is there is reason to suspect criminal activity or equivalent malpractice?
• Will the cameras only be used for a specific investigation, and will they be removed once the investigation is complete?
• Would it prejudice the investigation to tell workers that cameras are being used?
• Have you taken into account the intrusion on innocent workers?
• Has the decision been taken by senior management?

Cameras and listening devices should not be installed in private areas such as toilets and private offices, except in the most exceptional circumstances where serious crime is suspected. This should only happen where there is an intention to involve the police, not where it is a purely internal disciplinary matter.
In some cases, covert cameras installed for one investigation may turn up evidence of other criminal behavior or disciplinary offenses. You should only make use of this where the offence is serious, for example, gross misconduct or misconduct putting others at risk. It would be unfair to use evidence obtained covertly for minor disciplinary matters.
In some cases, covert monitoring may be covered by the Regulation of Investigatory Powers Act 2000 or the Regulation of Investigatory Powers (Scotland) Act 2000 (RIPA / RIPSA). You may wish to seek advice.

Video Servers Bridge The Gap

Network IP solutions are touted as the answer for security problems, but analog cameras dominate most existing camera configurations. Video servers span the distance between analog and digital systems, upgrading existing systems and holding tantalizing potential for newer uses.

One benefit of digital systems is faster response time, with video servers bridging the gap between legacy analog systems and digital IP systems. The universal function of a video server is to transform analog signals into digital signalsimportant in places with existing analog frameworks. 

Video servers, sometimes known as video encoders, bridge the gap between analog CCTV surveillance systems and digital IP based systems. Video servers are a great budget conscious, transitional product for those who are looking to gain some of the features and benefits of network based solutions but, aren’t ready to make the full jump.

If you’ve installed analog cameras in the past few years they’re going to be functional for quite some time.  There’s no need to shortchange that investment.  Video servers will allow you to maintain those analog CCTV cameras while enhancing your video surveillance system to provide the benefits of IP video.

Why Use A Video Server?

So you don’t have to discard your existing analog cameras! A video server allows your functioning analog CCTV video surveillance system to be integrated with a network video system. Gain the benefits of network video without having to replace what’s bought, paid for, and still working.

Coax Cable Is Expensive

Installing coaxial cable is expensive and once installed, hard to justify re-cabling with Cat 5. And with the average lifespan of an analog camera at 5 - 7 years, what fails first are the VCR’s and DVR’s used to record the video. Video servers not only allow you to keep existing analog equipment such as analog CCTV cameras and coaxial cabling but open up a true network video system because the video is consistently sent over an IP network.

A video server connects to an analog video camera via a coaxial cable and converts analog video signals into digital video streams that are then sent over a wired or wireless IP-based network (i.g., LAN, WLAN or Internet).

Video Server Advantages

• Use of standard network and PC server hardware for video recording and management instead of DVR’s or VCR’s
• Scalability in steps of one camera at a time
• Possibility to record off site
• Ability to remotely access and control analog cameras over an IP network
• Future-proof because the system is expanded easily by incorporating IP Cameras

Video Server Components

• Analog Video Input: For connecting analog camera using coaxial cable.
• Processor: For running encoder’s operating system, networking & security functions, encoding analog video using various compression formats, and video analysis. The processor determines the performance of a video encoder measured in frames per second (FPS).
• Memory: For storing firmware (computer program) using Flash, and for buffering of video sequences (using RAM).
• Ethernet/Power over Ethernet Port: To connect to IP network for sending and receiving data, and for powering the unit and the attached camera if Power over Ethernet (PoE) is supported.
• Input/Output (I/O) Connectors: For connecting external devices such as sensors, relays, and lights.
• Audio In: For connecting a microphone or line-in equipment and audio out for connecting to speakers.

What To Consider When Choosing A Video Server

• The number of supported analog channels
• Image quality
• Compression formats
• Resolution
• Frame rate & features such as pan/tilt/zoom support
• Audio
• Event management
• Intelligent video
• Power over Ethernet (PoE)
• Security Functionally

IP Convergence

Video servers are a great problem solver when you’re faced with the challenge of migrating a large investment in analog CCTV cameras to IP video.  Next up I’ll go into more detail about a very important benefit that video servers provide - Event management and intelligent video capabilities with the ability to use advanced video monitoring software

Employment Law Versus Human Rights Law for CCTV Cameras

It comes as no surprise to many that the India has more CCTV cameras per person than anywhere else in the world; leading human rights lawyers to warn that their almost constant use in our everyday lives raises data protection and wider privacy concerns, since they can be used in an intrusive way.

But what are the limits? At the workplace, employers are permitted to monitor workers in so far as it is necessary and proportionate to the management's reasons. CCTV monitoring is often undertaken for security reasons and is thus widely viewed as reasonable. It follows that employees naturally inspire reassurance from their respective employers that they are using CCTV responsibly.

The Information Commissioner's Office (ICO) published its first CCTV Data Protection Code of Practice in 2000 to help CCTV operators comply with the Data Protection Act 1998 (DPA) and follow good practice.

The Code of Practice: Monitoring at Work gives guidance on how to avoid employees calling in the lawyers over breaching the provisions of the DPA. The Code provides that before such monitoring is introduced, an impact assessment must be carried out to determine what (if any) monitoring is justified by the benefits of that monitoring. Under the DPA, any CCTV monitoring must normally be open and backed by fulfilling reasons.

The assessment should consider targeting the monitoring only at the areas of particular risk, confining it to areas where people's expectations of privacy would be low, using video and audio monitoring separately - cases where the use of both to be justified becomes rare. Its operation should only be where deemed necessary rather than continuous - although continuous monitoring may be justified where security is at risk. Finally, whether comparable benefits can be obtained by less intrusive methods and what adverse impact it may have on workers.

In making the assessment it is advisable for the employer to consult trade unions/employee representatives.

If the monitoring is introduced to enforce certain rules and standards, the employer must ensure that the workers are aware of and understand them.

According to one employment lawyer, the use of CCTV to monitor the actions of employees has potential implications in respect of the Data Protection Act and the Human Rights Act 1998 (HRA). If the surveillance is excessive, the implications may vary depending on whether the employer is a public or private body or individual.

If the employer is a private organization or company, then direct reliance on HRA is not possible. Nevertheless, all contracts of employment contain an implied term that employers will not - without reasonable and proper cause - conduct themselves in a manner likely to destroy or seriously damage the relationship of trust between themselves and employees. Yet, it is doubtful that CCTV cameras in obvious places in the workplace would violate this implied term.

On the other hand, an employer in a public body has an obligation to respect workers right to private life under Article 8 of the European Convention on Human Rights (as enacted by HRA). However, this right is a qualified right which means that it may be interfered with for a legitimate purpose in accordance with law and is necessary in the interests of national security, public safety or the economic well-being of the country for the prevention of disorder or crime, for the protection of health or morals, or for the protection of the rights and freedoms of others. The interference must be proportionate in achieving its aim. An example of disproportionate use may arguably be where cameras are put in toilets or changing rooms.

Ultimately, it should be borne in mind that despite the points outlined there is very little scope to impede employers making recordings. Placement and retention of footage must be in accordance with regulations under DPA. As this is a relatively recent development in the law, there are very few decided cases (the DPA does not apply to individuals' private or household purposes).

Assistance for employees comes from either expressing direct concerns to the employer which is the easiest way to resolve the situation or from a union if the worker is a member.

Any personal data collected must be stored securely. Also, regard should be had to the fact that anyone who is captured on CCTV will have a right of access to that footage under the DPA.

The Inner Workings Of CCTV Cameras

With the advancement in technology criminal procedures have also become more advanced. This is why the use of CCTV as a means of security surveillance has increased in recent years. CCTV cameras are used for spy and surveillance purposes. These stealth cameras are sometimes disguised whereas at other times they are placed in obvious locations to ward of the security threat. Nonetheless it is the highly advanced low light monochrome camera that provides the ideal security back up.

Some facts about the CCTV cameras

The CCTV sends out video signals that are directly encoded and fed to a 110 volt power line. You will find all kinds of CCTV cameras out there to come with a companion decoder. This device can plugged anywhere including an ordinary television set at your home. CCTV cameras make use of line level RCA type cables which are the standard cables for all kinds of video output. One of the most advantageous facts about CCTV cameras is the use of infrared technology. This advanced technology gives CCTV cameras the ability to pick up crystal clear video images even in total darkness. The best of CCTV cameras will be able to pick up images in pitch dark up to a distance of thirty feet.

One of the things that have led to the widespread use of CCTV cameras is their durability. You will be able to find CCTV cameras that have the ability to operate when situated at a distance of up to two thousand feet from AC wiring. CCTV cameras will also be able to deliver you top quality picture even when the power lines are loaded with other heavy electronics. Another plus point of the CCTV camera collection is its ability to capture images in an incredible wide angle view.

The technology embedded in CCTV cameras enables them to pick up even the slightest of changes. They are highly sensitive and will be able to deliver you clear images even in total darkness. Some CCTV cameras give you the ability to increase their infrared capability by adding supplemental infrared floodlights.

CCTV cameras are incredibly versatile when it comes to their usability. The fact that you can directly record the captured image onto your home VCR makes it very convenient. Plus the fact that you can use your very own TV set for monitoring purposes.

The latest releases in CCTV cameras provide the ultimate security solutions for home owners and business enterprises alike.  Interested individuals can take advantage of the easy availability of CCTV cameras through the internet. There is a plethora of choices for those seeking CCTV cameras with the different models having varying features. You can check to see which CCTV camera meets your requirements and pick up a bargain deal using the internet. Rest assured you will be able to find one that meets your requirements and fits your budget.

When Lightning Strikes Alarm Systems

April showers bring May flowers, or so goes the old cliché. Warmer weather also brings with it thunderstorms and power surges galore. All too often the result is false alarms, lost data and the destruction of high-tech electronic equipment.

Although lightning is a major concern during good weather, it doesn't have to be warm out for electric motors, smelting operations, heavy industry and other electrical concerns to spell big trouble for the equipment for which fire and burglar alarm technicians are responsible.

Lightning is a common concern for alarm technicians because of the suddenness with which it can strike. The damage that it can cause may involve a lone device connected to an internal low-voltage cable, like an addressable manual fire pull or an individual circuit board. Or it might involve an entire motherboard within a fire or burglar alarm panel.

Sometimes the damage is light while other times it can be catastrophic, tearing through the system from one end to the other. Having a fair understanding of how lightning works and by using good installation practices, along with quality equipment, technicians can limit the amount of damage that does occur.

Mechanics of a Lightning Strike

Any device that connects to a metallic wire can suffer damage at the hand of lightning. This is true whether the strike is direct to the cable itself or indirect by virtue of inductance. Sometimes no matter what you do, lightning will do irreparable harm.

Concerning a direct hit to equipment, lightning can enter through multiple paths from outside the structure. A good example is a campus environment where there are many buildings.

Lightning also can enter the structure through the public electric bus via outside power lines or one of the many paid subscription services now available. Examples include conventional telephone, cable television networks and satellite dish systems.

In a burglar or fire alarm system, once lightning enters the equipment through one of the methods cited above it can migrate to a signaling line circuit (SLC), initiating device circuit (IDC), notification appliance circuit (NAC) or some other low-voltage line. Another example is the coaxial cable or twisted pair unshielded wire that carries video images in a CCTV system.

"The focus is usually on SLC loops [burglar and fire alarms], low-voltage data [networks] and coax cable [CCTV].

Manufacturers are well aware of the problem lightning poses and for this reason they commonly build a limited amount of surge protection into their electronic systems at the point of manufacture. In most cases this is done right on the motherboard itself.

This ploy most often includes add-on printed circuit (PC) boards and any number of subsystems, such as smoke detectors, glass breakage sensors and others. And yet damage or total destruction can and often does occur when lightning appears on the scene.

One fire alarm manufacturer uses optical isolation on the data loops to minimize lightning damage. Damage in this case often occurs when lightning induces a high voltage current in the internal wiring of a building. This can be especially problematic in campus environments where data lines travel under ground between buildings.

This design incorporates the idea of isolating the grounding differential from the other buildings. Nice little spark gaps and it does help, but the problem is, when incorporating second-rate surge suppression, you get a feedback loop up the case ground into the smart chip.

When you consider the multiple pathways over which lightning can travel, you must also think about distance with regard to proximity as it pertains to the surge protection device that acts to clamp the surge voltage and route the strike current to earth ground.

This is true whether it involves external surge protection or those internal to the device itself. Many years ago an engineer told this writer that lightning will often travel well beyond the point where the surge voltage is clamped. All too often this ends up damaging critical circuits, not to mention the possibility of arcing within the panel itself.

The most panels can handle some of this current, but not all of it. This is especially true where there's a significant voltage differential between equipment grounds of all the interconnected equipment.

Think Ahead When Installing

As mentioned earlier, one common application where lightning can cause considerable damage involves integrated systems across multiple buildings. Because of the matrix of wires that travel to and from each building, being installed either overhead or underground, the propensity for damage is considerable.

In this case a single head-end system may be employed to provide a number of low-voltage services, such as fire, security and/or CCTV protection. Here, especially proper precautions must be taken, such as the use of quality surge protection.

One case in point is a motel with multiple buildings serviced in the summer of 2008, by Nick Markowitz, owner of Markowitz Electric Protection of Verona, Pa. According to Markowitz, the location experienced a lightning strike that damaged a fire alarm system, three cameras and a washing machine. The lightning affected systems in three separate buildings by first entering a restaurant and then traveling throughout the entire campus.

"The camera system is one of those cheap cameras-in-a-box deals that uses four-wire telephone cable. One of the cameras is located in the restaurant and is fine, but another one took a hit and the wiring was damaged," says Markowitz. "The other two cameras were converted from phone wire to inline powered coax and lightning took out the converters and power injectors."

Lightning entered through one of the cables that crossed between the buildings, Markowitz reports. A close examination revealed that there wasn't any surge protection on any of the low-voltage cables that serves video or any other centralized system. And yet damage was spotty, which Markowitz found puzzling considering the severity of the hit.

"I find it strange that the monitor and one of the other cameras were fine but all the rest was trashed. Usually when lighting strikes like this, everything goes at once," he adds.

Equipment Circuit Design Changes

Manufacturers have changed the way they construct and package components contained in their low-voltage systems. Included is the way those components are installed on PC boards. Both of these factors have altered the way alarm technicians protect their electronic systems from lightning, says Pecore.

"In 1997, Stormin Protection Products officially became an engineered lead business because the projected sales in the area of low-voltage surge suppression for fire alarm, CCTV and access control systems will be in greater demand as the progress of SMT [surface-mount technology] literally took over the industry," says Pecore.

SMT technology allows manufacturers to reduce power consumption as well as extend the length of time batteries will provide backup power. If nothing else SMT components have allowed manufacturers to reduce battery size to meet a specific code requirement, such as standby time. SMT technology poses a problem because it represents a relatively low impedance to lightning.

“SMT technology for an old guy is a dirty word. It spells out one thing, nothing but trouble,” says Pecore. “Manufacturers took all the linear and high capacitance devices off the board and left me with a featherweight that if I hiccup just right, it will blow.”

Design engineers have eliminated linear power supplies, replacing them with Wheatstone bridges. Also, low-impedance capacitors and resistors have replaced heavy-duty capacitors and resistors, and smart chips have replaced entire printed circuit boards. 

“Low Pico Farad devices have also replaced other components — all for the sake of reducing current draw,” says Pecore. “As a result of these changes, fire alarm panels (and other electronic systems) have become more susceptible to surges, impulses and ground strikes.”

The idea is to raise the impedance of the panel, not lower it, and to do this the installer has to look for ways to create an alternate path that looks more inviting to high-voltage lightning than the panel’s motherboard.

According to Pecore, the answer is an inline series hybrid three-stage, two-tank circuit that works to impede strike current while shunting it to ground. This is accomplished by focusing on the characteristic frequency associated with lightning.

Thanks to SSI Magazine FOR HELP & Thanks to John Pecore, President at Stormin Protection Products Inc

Outdoor Wireless/ Wire Security Cameras – All You Need to Know

A little research can go a long way in ensuring that the right equipment is purchased at affordable prices. Most security equipments have a number of options available in the market and improper understanding can either lead to a bad purchase or an unnecessary purchase. Let us understand the basics of outdoor wireless security cameras that will help you in buying the right outdoor camera for your security system.

Different Outdoor Wire / Wireless Security Cameras

Analog and Digital Cameras

These are the time-tested devices that have been used since a long time in different security systems. They can be connected to the video surveillance systems through wires. These cameras are less expensive as compared to their digital counterparts but they are difficult to install.

Power

You can use wired devices that can be powered by connecting their wires to the central power unit. A better option is the wireless camera that does not need wiring but needs to be connected to power outlets. In case you are installing cameras where power outlets are not available and cannot be made available, then consider using wireless cameras that run on batteries. These cameras can be easily installed at any place but need to be constantly monitored for battery changes.

Lux Number

Outdoor Cameras are exposed to different lighting conditions throughout the day and these conditions also vary in different weathers. Use cameras with low Lux number which signifies that the cameras can cope with dim lighting conditions. You should also invest in night vision cameras that use infrared technology to capture images even in pitch dark conditions.

Weather Proofing

Cameras are sensitive electronic equipments and hence, they need to be protected from the vagaries of nature. While investing in an expensive camera make sure that you also buy a weather proof casing to guard your camera from excessive heat and moisture. In very cold regions, cameras with insulated casings should be purchased. For hot weather conditions, casing with exhausts will come handy.

Protection from Vandalism

It is important to protect your equipment from vandalism. Buy an outdoor camera with sturdy material. Use a casing that can protect any on-the-spur attack on the camera. You can also buy dome-shaped cameras and casing that gel well with the surroundings and make these camera less visible, thereby, protecting them from any danger.

Ideal Transmissions

Using wireless devices has a drawback that there signal transmission can be weak. Make sure that you buy equipments that can transmit data over the distance that you require. Factors such as big trees, metals in the walls and bad weather can hinder wireless transmissions. Hence, it always better to invest in good devices with wide transmission range. You can also invest in good quality signal receivers that can capture low quality inputs as well.

Picture and Sound – While selecting a camera, pay special attention to its picture quality. A low screen resolution will not be able to give quality inputs. Audio wireless outdoor security cameras can also be purchased with audio compatible devices.