PERTANYAAN SEPUTAR CCTV

CCTV Technical FAQ's
its-home-security.co.uk

Constant recording or motion detection?
Do you want to see everything the cameras see throughout the day and night or would you prefer them to be set on motion detection so they record only what moves past them. Motion detection allows for greatly increased recording capacity on the DVR.
For example if the your front door camera was set up correctly with the motion detection setting, you would only see who had come to your front door throughout the day with out having to manually wind the DVR forward.
How do I backup my Footage?
The recordings can just tape over the old footage after 30 days or so or you may want to back them up to CD, network PC or USB. These choices will all affect the budget for your home security CCTV system.

How do I choose the correct camera for my application?

This in general is a comparatively difficult decision. Many aspects of the installation must be taken into consideration in order to obtain the correct performance that meets your requirements.

A high resolution camera should be considered where greater detail of scene is required. E.g. Colour 460 TVL, Monochrome 570 TVL. Choosing a more sensitive camera will improve reproduction in poorly lit areas. The sensitivity of a camera is indicated by the minimum amount of light in order for the camera to produce a usable picture. e.g. Colour 1.0 Lux at F1.2.

A conventional camera produces a pale backdrop when an object is shot against a bright background. BLC (Back Light Compensation) will counter strong light sources retaining picture quality.

Concentrated light sources directed towards the camera (e.g. car head lamps) can be inverted by an optional peak white inverter or an eclipser function. This has the effect of bringing detail to areas and making an object clear, that would otherwise be shadowed.

What features should I look for in a CCTV Digital Video Recorder (DVR)?

All DVRs are definitely not made equal!

There are several factors that are critical to consider when purchasing a DVR, especially when comparing price. The most important factors to look at are the number of cameras supported, frames per second (fps), compression technology, hard drive space, network connection / remote viewing capability, motion detection, scheduling, and ability to save video and audio to a CD or flash drive. You should also look for easy and comprehensive search capabilities (check out our 'Smart Search' technology) and audio support. The setup and user interface should be intuitive and easy to operate.

What is frames per second?

The frames per second (fps) relates to how many pictures the DVR will record in a second. Real time recording is about 30 fps on each camera. To calculate the fps per camera take the total fps in the system and divide it by the number of video inputs. For example, a 60 fps digital video recorder with 4 video inputs would result in about 15 fps per camera. The technology has finally gotten to the point now where real time recording is affordable. If you are recording cash registers or something similar then you should definitely invest in real time recording.

How big a hard drive do I need?

The amount of hard drive space is very important because it will limit how many days of recording you can store before the system has to start recording over the oldest video. Each DVR will have its storage capacity listed in the specifications. But this calculation is just a rough estimate as there are many factors that affect hard drive use. The most critical factor being the compression format used by the DVR (for more info on compression formats click here). But also the type of cameras that are connected to the DVR make a difference (specifically the chip size and resolution) and also the features that are selected on the DVR. If you use the scheduling or motion detection features or tune down the frame rate that will extend the storage capacity of the unit. Even the field of view (what you are recording) will affect the storage capacity - the more complex the image, the more hard drive space it will take to capture the complexity.

What is the difference between a PC-based DVR and an Embedded DVR?

A PC-based digital video recorder is basically a personal computer that has been modified with hardware and software to work as a DVR. An embedded digital video recorder is a machine that has been manufactured specifically to work as a DVR. In embedded DVRs there is typically one circuit board with software burned into the chip.

There used to be significant differences in features between the PC-based and the embedded machines. But with recent advancements in the embedded DVR technologies the differences are becoming less. The advantages of an embedded digital video recorder is that they are extremely stable and reliable since they contain fewer parts. The software is often written in basic machine code or Linux code which tends to be more stable than Windows software. The advantages of the PC-based digital video recorders is that they are easier to interact with because you use the on-screen menus and a mouse (as opposed to embedded which you interact with more like a VCR - via buttons). And you tend to have more features and options on the PC-based machines.

How does a CCTV digital video recorder work?

A CCTV digital video recorder (or “DVR” for short) is essentially a computer that saves security video images to a hard drive. Most security cameras in use today capture an analog picture. The DVR converts the analog signal to digital and then compresses it.

Many cameras can be connected to one DVR. DVRs generally come with 4, 8, 16, or 32 camera inputs. The DVR will allow you to view all of these images at once or one at a time, and all of the video is saved to the hard drive. Additional switches, quads, or multiplexers are not required.

Are security digital video recorders hard to install?

Not at all. You simply plug the cameras into the back of the unit. For the PC-based: Plug in the power, monitor, keyboard and mouse - just like a regular computer. You will receive instructions on how to set up the machine with your shipment.

What comes with the DVR?

Most of our DVRs come standard with an 120 gig hard drive (unless otherwise noted). They also include the software (for setup, local, and remote viewing), power cord, and documentation. PC-based machines also come with the mouse and keyboard. You just need to add the cameras, whatever cable you need, and a monitor. For embedded machines you can use a TV set or security monitor. For PC-based machines you need a standard computer monitor. Also, we have on-site technical support available at no additional cost.

Why doesn't the computer monitor come with the PC-based Digital Video Recorders?

We don't supply the computer monitor with the DVR because frankly you can get one cheaper and easier locally. Large computer stores such as Best Buy or CompUSA sell these monitors practically at cost. And due to thier heavy weight, they are very expensive to ship (and subject to damage). Also, we found that many of our customers have spare computer monitors available.

How do I see pictures from a remote site?

You can view the camera video over the internet using a modem which is slow but can display 1 or 2 frames every 5 seconds. Better is a DSL or cable modem connection which can generally display 1 frame per second. When viewing remotely, the refresh rate is restricted by the communications medium (your internet connection speed). When viewing or playing back locally, the display is dependent of the unit's frame rate (fps). You will need a static ip address available to assign to the DVR (more about this in your documentation).

What is 'Smart Search'?

Our PC-based DVRs come standard with smart search capability. This allows you to highlight one area of a captured image and look for changes just to that area. For example, if an item is stolen off of a counter... you can go to a moment in the video where the item is still on the counter, then highlight the area around the item and search automatically through the video for the moment in time when that particular area changes, that is precisely when the item is removed and then view that part of the video. Pretty slick!

How do I set up a camera and lens for use in Low Light conditions and or with Infra Red Lighting?

The answer to this is the same as that for questions relating to Back Focusing on Page 31 and 34, with the addition of the following:

When setting the back focus of a Colour camera for low light conditions you should place an ND1 (Neutral Density) filter in front of the lens. When setting the back focus of a Mono camera for low light conditions you should place an ND3 (Neutral Density) filter in front of the lens. When setting the back focus of a Mono camera fitted with I/R lighting for low light conditions you should place an IRP (Infra- Red Pass) filter in front of the lens.

Should you not have any of the above filters you may have to attend site during the hours of darkness.

I have installed a new camera and lens why am I unable to obtain a sharp image?

The most common resolve to this is to ensure that both camera and lens are the same mount i.e. ‘CS’ mount lens on a ‘CS’ mount camera and a ‘C’ mount lens on a ‘C’ camera.

What are OSD cameras?

OSD (On Screen Display) cameras have a menu system within the camera assembly that can be accessed in order to set functions such as Iris levels, AGC on/off and most features of standard and advanced cameras.

Why do I have a clear sharp picture during the day and it is out of focus at night?

This is due to the depth of field changing as the light conditions change and can be easily overcome by following set procedures.

When can I use a manual iris lens?

A general rule of thumb is only to use a MI lens in an internal application. This is because you are reliant on the electronic circuitry of the camera compensating for light changes in the scene and this is not able to compensate to the same degree as that of an Auto Iris lens.

How do I back focus a camera fitted with a fixed focal length lens?

This is achieved by following five simple steps.

• Set the physical focus of the lens to infinity (clockwise from the front).
• Aim the camera at the subject to be viewed.
• Release the camera back focus mechanism.
• Adjust the back focus to obtain the best possible picture.
• Secure the cameras back focus mechanism.

Can I fit a 1/3" Lens to a 1/2" camera?

The simple answer is NO.

How do I connect an Auto Iris lens to a camera?

This is usually performed by a simple plug-in connection to the rear or side of the camera. However you should always refer to the relevant camera handbook.

What is the difference between Auto Iris and Direct Drive Lenses?

An Auto Iris lens is one that automatically adjusts its iris for changes in the scene lighting levels. The motor that opens and closes the iris is driven by an Amplifier that processes a small electronic signal changing with the light level.

A Direct Drive 'DD' lens does not have this Amplifier and can only operate with a camera fitted with one.

A camera specification will indicate the available output options.

Does the ‘f’ stop matter when choosing a lens?

Yes, lenses are usually specified as having a minimum and maximum ‘f’ stop rating; the ‘f’ stop is a measure of how efficiently the lens allows light from the scene, to pass through the lens and onto the camera CCD sensor. The maximum aperture (when the lens is fully open), is the minimum ‘f’ stop number and the minimum aperture, (just before the lens completely closes) is the maximum ‘f’ stop number.

A low minimum ‘f’ stop number means that the lens can pass more light through during dark conditions, which will produce better pictures at night.

A high maximum ‘f’ stop number may be necessary where there is a high level of light or reflection. This will prevent the camera ‘whiting out’.

How do I Back Focus a camera fitted with a ZOOM Lens?

This can be achieved by following these steps.

• 1. Set the lens to full wide angle view.
• 2. Set the physical focus of the lens to infinity (clockwise viewed from the front).
• 3. Aim the camera at an object at least 30 Metres away.
• 4. Release the camera back focus mechanism.
• 5. Adjust the back focus to obtain optimum clarity.
• 6. Zoom the lens in to full telephoto and focus on a nearby object.
• 7. Keep this object in view as you slowly zoom out and if all is set correctly it should remain in focus (track).
• 8. Secure the back focus mechanism.

How do I set up an Auto Iris lens?

An Auto Iris lens has two ‘pots’ on the side commonly marked ALC (Automatic level control) and LEVEL.

The ALC control has settings of PEAK and AVERAGE (P+A).

The LEVEL control has HIGH and LOW settings ‘H+L’.

ALC

The adjustment allows control over any bright areas in the scene e.g. sun reflection through windows, street lighting etc. There are two settings PEAK and AVERAGE.

If set to PEAK, bright areas in the scene are taken into account more, reducing the contrast in the surrounding area. This allows more detail to be seen in the bright areas.

If set to AVERAGE the lens takes the bright areas less into account which usually causes over brightness or flare in these areas, but raising the contrast of the surrounding area.

LEVEL

The only correct way to set the VIDEO LEVEL is by the use of an oscilloscope, for most Engineers this is not an option.

A more practical method is to use a service test monitor and a camera that you know has been set up correctly to 1 volt peak to peak.

Put the video output from this tested camera into the test monitor and adjust the contrast and brightness until you are satisfied with the picture. Mark the contrast and brightness controls so that you can set them to this position again.

Set up each camera adjusting the ALC (as above) then adjusting the LEVEL to obtain a picture similar to that achieved with the test camera. (Making sure that your test monitor is set to your marked positions)

NB: On most zoom lenses the ALC adjustment is a speed control for the Iris motor and is best left in the mid position. The Amplifiers on Auto Iris lenses are sensitive; so adjust the LEVEL and ALC with a proper trimming tool instead of an ordinary screwdriver, which can induce small voltages.

What size monitor should I be using?

The correct size monitor is dependent on its use e.g. the number of images to be displayed at any given time, the viewing distance and the available space.

What is Video Termination?

This is the end of line resistance of any CCTV system and this should be set to 75 ohm. Should you encounter any double image or ghosting this is more often than not caused by two pieces of equipment in series both having the 75-ohm switch set on. Only the last piece of equipment should be set at 75-ohm.

What camera housing should I use and at what IP Rating?

Camera housings come in various shapes and sizes. With regard to the correct IP rating protection, this will range from dust and water ingress. This system is governed by a number of European and British standards.

IP55

• Protected against dust - limited ingress.
• Protection against low pressure jets of water from all directions – limited ingress permitted.

IP65

• Protection against dust - no ingress.
• Protection against low pressure jets of water from all directions – limited ingress permitted
• Protection against high pressure water from all directions - limited ingress permitted.

What is the difference between simplex and duplex multiplexers?

Video multiplexers are designed to allow recording of several cameras onto one recorder.

Simplex

A simplex machine is best suited to applications where recording only is the priority. Simplex machines cannot display multi screen images (i.e. quad, 9 way and 16 way split) while in the record mode.

Duplex

If an operator is monitoring the system (i.e. security guard) then a duplex machine is more suitable. A duplex machine can provide screen splits and user selectable images without affecting what is recorded onto the recorder. Should you use two recorders, it becomes possible to record and playback simultaneously.

What is the difference between Standard VHS and SVHS recordings?

In general the main difference apart from cost is the increase in overall resolution. A standard VHS machine may achieve in the region of 300 TVL (mono) whereas S-VHS machines may achieve in the region of 400 TVL. However this being achieved will depend on the correct ancillary equipment being used.

Which pan and tilt unit should I use?

The choice is wide and varied dependent on the system requirements. You may require Top mount, Side mount, 230V AC or 24V DC to name just a few.

TOP MOUNT

• Pro: Can fit two IR lamps on the side of the Pan/Tilt. These act as a counter balance enabling you to use a lighter duty Pan/Tilt head.
• Pro: Compact size.
• Con: Restricted tilt often -45 to 0 dependent on the housing fitted.
• Con: Cannot be inverted.

SIDE MOUNT

• Pro: Can be inverted.
• Pro: Often cheaper.
• Pro: Large tilt often +or- 180
• Con: Difficult to mount IR lamps.
• Con: Generally large size.

What type of illumination can I use with colour cameras?

Only lighting within the visible wavelength should be used with colour cameras. Tungsten Halogen is often the recommended source of lighting.

Can I use I/R Lamps with colour cameras?

The answer to this is a definitive NO. Colour cameras are typically fitted with an IR cut filter and will not allow IR light in excess of 700Nm to pass resulting in the camera performing poorly in these circumstances.

What is an ISDN Telephone Line?

An ISDN (Integrated Services Digital Network) Line is a digital system allowing a camera to be updated at a rate of 15 frames a second.

What is a PSTN Telephone Line?

A PSTN (Public Switched Telephone Network) Line is an analogue network allowing a camera image to be updated every few seconds and is therefore slower than that of an ISDN network.

What is an ADSL Line?

Also known as Broadband, an ADSL (Asymmetric Digital Subscriber Loop) line is a form of Digital Subscriber Line in which the bandwidth available for downstream connection is significantly larger than for upstream. Although designed to minimise the effect of crosstalk between the upstream and downstream channels this setup is well suited for web browsing and client-server applications as well as for some emerging applications such as video on demand.

What is a Leased Line?

Leased Line, sometimes known as Kilostream, Megastream or Private wire. This is NOT a dial up line but is connected 24hrs a day and is usually subject to an installation charge and a quarterly bill.

What is full picture update?

Full picture update is a technology that enables a transmission system to update a high quality full picture refresh at very fast speeds.

Do I have to use a Regulated Power Supply?

In general the answer is yes. Most manufacturers will recommend the use of such power supplies as standard with their equipment. You should always consult the manufacturers specifications prior to the connection of any power supply.

What is the maximum distance I can run 12vdc when powering a camera?

This is a commonly asked question and there is no simple answer. Some manufacturers may recommend that their cameras can be run over (X) distance with (Y) cable. This however should still be considered as a general guide. Cable conductor size and installation route must also be taken into consideration. If you are unsure, we would recommend that you contact Technical Support for guidance.

What is the difference between RG59 and URM70 Coax?

In general there is little difference. However RG59 is a hard drawn conductor and is best suited to fixed camera installations. URM70 has a multi stranded centre conductor and is more suited to installations such as PTZ cameras.

What is a ground loop?

An AC current that can be produced in a cable. This is usually caused by parts of the system being fed from different electrical sources resulting in different earth potentials at each end. The result is interference on the signal, usually in the form of dark bands across the monitor and on occasion tearing in the top third of the image.

How can I eliminate ground loop faults?

This can be achieved in a number of ways, the easiest of which is the installation of a Ground Loop Isolation Transformer. This is best installed at the monitor or recording end of the system.

What is the correct level for a video picture?

The correct level is 1 volt peak to peak. This can only be accurately set either with an oscilloscope or with a video level meter.

How often should I replace my video tapes?

In general it is recommended that all video tapes should be replaced after a period, no greater than 20 passes of each tape. That being 10 record and 10 play back. This will also be dependent on the quality of tape being used and that the recording equipment is in good operational condition.

Manual or Auto Iris Lens?

The iris is the part of the lens that determines how much light falls upon the camera CCD sensor.

The Manual Iris 'MI' lens has this fixed at the time of installation. As the light levels change in the scene, the lens can do nothing to prevent either too little or too much light entering the camera. Virtually all cameras employ an Automatic Electronic Shutter 'AES' to compensate for these variations when fitted with an MI lens. However they are only able to cope with a relatively small change in light levels.

An MI lens should never be used in an external situation, as the camera will be unable to cope with large changes in light levels. Use an Auto Iris ‘AI’ lens in this case, or indeed anywhere where large scene illumination changes take place.

The advent of new sensor technology such as PIXIM may result in a change to this situation in the future.

How often should I replace my IR Lamp Bulb?

Installers and end users are often disappointed by the life they get from Halogen bulbs.

Manufactures quote life expectancy figures as 'Mean Time'. They are not a guarantee of the bulb life. This simply means that on average after a number of hours quoted by the manufacturer HALF OF THE BULBS WILL HAVE FAILED. If the 'Mean Time' of 4,000 hours is quoted, half the bulbs will fail within that 4,000 hour period (5.5months).

Matters appear worse during the period of October to March, obviously because of the longer hours of darkness. During this period, lamps may be on as much as 16 hours each day. A simple calculation may be used in order to provide adequate maintenance on these systems.

If you have 5 external cameras each with 2 lamps that gives us a total daily lamp usage of:
10x16hr = 160 hours per day.

If the lamp has a mean life expectancy of 4,000 hours, this means that you can expect a bulb to fail every:
4,000/160 = 25 days.

You should make sufficient provision for this within a maintenance contract.

"DVR" Cards,

• Pentium 4 Processors
• Windows XP Pro or 2000 Pro
• 845 Chipset "Boxed" Motherboards

How do I install the card & software?
1. Insert PCI Card into the system and turn the system on.
2. When windows detects "New Hardware", CANCEL out of all the driver installation screens.
3. Open the "Drivers" folder of the DVR software and initialize the "Installer.exe" icon. Proper Drivers will be installed automatically.
4. Open the "DVR Main" system software folder and run "setup". Setup will install the proper software for the card that is in the system.
6. INPUT & REMEMBER the master USERNAME AND PASSWORD when prompted.
7. You must first allocate disc space for the DVR system through the "Disc Management" option in the settings screen. Click the "Settings" Icon on the desktop to enter settings.

Graphic cards are said to have great influence on the DVR Cards. What graphic cards do you recommend?
The first recommendation would be the graphic cards manufactured by ATI(Rage 128pro, Radeon) or above.
Another recommendation would be the GeForce2 MX 200/400, or above from nVIDIA, We recommend using the drivers which we supply with our DVR software.

What are the backup devices supported by the system?
Data backup devices include CD-RWs, DVD-RAMs, DVD-RWs, DATs, etc., any device that Windows recognizes as a drive, and you can also backup on a network drive.
The unit of the data is 1 minute, and can only be viewed through the supplied Backupviewer. Data backup is also possible on the Search program, where it can be saved in AVI format, making it conveniently viewable through the Windows Media Player(by enabling "View-Caption" from the menu, you can also conform information data).

Windows 98 uses the FAT32 file system, while Windows 2000/XP also supports the NTFS file system. Which file system should I use?
Each file system has advantages and disadvantages to them, but we recommend the FAT32 method over the NTFS system. Using the NTFS system as your database can result in small data glitches.

WHAT IS THE DIFFERENCE BETWEEN A PC-BASED DVR AND AN EMBEDDED DVR?

A PC-based Digital Video Recorder is basically a personal computer that has been modified with hardware and software to work as a DVR.  An Embedded Digital Video Recorder is a machine that has been manufactured specifically to work as a DVR.  In embedded DVRs, there is typically one circuit board with simple software burned into the chip.  There are advantages and disadvantages to each type of DVR.

The advantages of an embedded digital video recorder is that they are extremely stable and reliable since they contain fewer parts.  The software is often written in basic machine code or Linux code which tends to be more stable than Windows software.  Also the picture that you get on the monitor usually looks better (especially when viewed full screen) than PC-based DVRs because there is less compression.  The disadvantages are they have less options.  Most do not have remote viewing capability.  They generally have slower recording rates.  Sometimes embedded DVRs do not have CD burner so the only way to get video out of the machine is to copy it via the LAN (if it has the connectivity) to another computer or to hook up a VCR to it.  Since they generally have less compression they use more hard drive space so you can fit fewer days of recorded video on it.  And you do not have as many options to upgrade the hard drive space as the PC-based systems.

The advantages of the PC-based digital video recorders is that you have many more features and options available on the units.  For example, some of the options you get on the PC-based machines that you don't get on the embedded is the ability to set many options like motion detection and you can completely control the PC-based DVR remotely.  The software is easily upgradeable when new enhancements are made.  You interact with the software via mouse or an optional keyboard so its much more easier to use (with the embedded systems you set them up with buttons like in a VCR).  A CD ROM burner is included so storing video off the unit is easy.  Compression is usually better so it uses less hard drive space and you can customize how much hard drive space you want on the unit.

PC-Based DVR FAQ

Faq from http://www.discount-security-cameras.net

I need the static IP address information for my connection.

Contact your Internet Service Provider (ISP) and request the information. Only your ISP can provide you with this, we cannot.

Do I have to make changes in the DVR software for me to connect remotely?

No. The only option is to allow incoming connections. This is on by default There is no place in the DVR software to put any IP information.

I have the static IP information for my connection where do I enter that information for the DVR?

The DVR is like a standard Windows XP computer. Follow the instructions from your ISP to enter the information into the network adapter. Or click this link to read the document of how to do this.

How many Frames Per Seconds will I see with an 8 Camera 120 FPS DVR (or any other DVR)?

There is no way to tell exactly how fast your video will come across the Internet. The speed depends on your connection to the Internet and the DVR's connection to the internet as well. The same applies for a modem however the speed of a modem is extremely slow and you will not be happy with the performance over a modem connection.

How many computers/people can I have connected to and viewing a DVR remotely?

Up to 50 connections to the DVR can be made at a single time. With a modem however there can be only 1 person connected at one time due to phone line restrictions.

What are the RCA jacks for on the back of the DVR?

They are for switching video out. They only display one camera - and they switch to the next camera at timed intervals.

I want to view my DVR screen on a TV just like I see it on my computer screen.

You will need to buy a separate module that will allow you to do that. - we sell them for