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Network Webcams blog
Archive for the ‘IP Camera Glossary’ Category

Glossary: Converting Analog CCTV to IP

October 1st, 2008 by Kevin Bowyer

Most companies with existing CCTV systems will have largely analog cameras and recording devices, probably a tape-based VCR. This is still by far the most common system in use the world over. Analog systems are increasing in obsolescense and lack the flexibilty and cost saving which new-style IP CCTV offers businesses of all sizes.

It is easy these days to convert an analog CCTV system into a hybrid IP CCTV system which offers most, if not all of the benefits, flexibility and scalability a full networked CCTV installation would offer.


Glossary: CCTV Monitoring Centre

October 1st, 2008 by Kevin Bowyer

There are numerous means of monitoring your CCTV installation including on-site recording, via email or mobile phone, or using remote access to local recordings on your CCTV recording station. Another way is to have your premises monitored by a professional CCTV Alarm Monitoring Centre.

A CCTV Alarm Management Centre has remote access to your CCTV system and instructions from you on what to do in the event of an alarm, or a breach in your premises’ security. Actions they might perform include logging into your cameras to view and/or record what’s going on, setting off alarms on your premises, activating lighting or calling the Police.


Glossary: IP camera ports

September 30th, 2008 by James Drinkwater

When beginning to understand home networking in regards to IP cameras, ports can often be difficult to understand. Put basically, every network device, such as an IP CCTV camera or computer, usually only have one single IP address, e.g. However, these network devices can often have more than one program looking to receive information over the IP address. An example of this on a PC could be an internet browser, FTP server and email program all looking for information. The computer thus needs a method of finding out which program should receive which information.

This is where ports come in. A port is a number from 1 to 65536 which will identify which program should receive the information. From the previous example, internet browsers operate on port 80 with FTP servers on 21 and email on port 25. This port number is added to any chunk of information which is sent across the network and is passed by the computer to the correct program.


Glossary: Mobile phone browser support

September 30th, 2008 by James Drinkwater

Some IP security cameras such as the Vivotek FD7131 and Panasonic BB and BL IP cameras offer dedicated mobile phone browser support. With This, users with internet-enabled mobile phones can monitor their IP security installation from anywhere in the world without the need for bulky computers or landline internet connections. Mobile phones connect to the internet through the GSM network so as long as you are within range of this signal, you have access.

The Panasonic mobile phone browser allows a viewer to see a static image of their camera and is available by navigating to http://mobile. Those with pan and tilt IP security cameras can use the 8, 2, 4 and 6 keys on their keypad to move their camera view. Vivotek on the other hand offer a 3GPP (3rd Generation Partnership Project) viewer with their IP camera. This makes use of 3G compatible phones and requires 3G signal coverage, which is not available in all areas, but allows users to pull motion video streams from their IP camera.


Glossary: Power over Ethernet Midspan

September 30th, 2008 by James Drinkwater

When used in conjunction with Power over Ethernet compatible equipment such as an IP CCTV security camera, a midspan is the device used to combine power and data into a single cable. The device connects from your existing network to your camera, as well as to the mains power point, and provides power as required.

The way a midspan works is that whenever a device is connected to it, a small amount of power is transferred along the cable; not enough to power the device, but enough to power the port. The midspan will then send a short signal over the network to ask the device if it needs power. A Power over Ethernet enabled device will return a message saying that it does require power which the midspan will then supply. A device which does not support Power over Ethernet will not reply and thus will not receive any additional power. This means that you can never damage a device that does not support Power over Ethernet by plugging it into a midspan.


Glossary: Automatic Gain Control (AGC)

September 26th, 2008 by James Drinkwater

In low-light conditions, some IP security cameras use Automatic Gain Control (AGC) to artificially improve their “dynamic range” and produce usable images. AGC is basically a from of amplification where the camera will automatically boost the image received so that objects can be seen more clearly. In normal light conditions the camera will display a normal picture. However, when the light quality drops below a certain level the camera will begin to boost the signal to compensate for the lack of light.

The advantage of this technique is that your camera will produce images in much lower light conditions than standard. The downside is that the amplification is not only on the usable data in the image but also the background noise. This means that the more you amplify, the more noise you will see and the poorer the image quality will be.

Glossary: Image transfer via FTP

September 26th, 2008 by James Drinkwater

FTP stands for File Transfer Protocol. This is a network protocol and is a method which can be used by IP security cameras to transfer images from the camera to storage.

FTP is a client/server system which means that there must be one FTP server and an FTP client. An FTP server is essentially a network connected hard disk. Whenever data has to be transferred, a client, such as an IP camera, will connect to the server. Data will then be sent from the client to the server for storage. Once data is transferred the client will disconnect. An FTP client can only connect to one server at a time but an FTP Server can allow many different clients to connect simultaneously.


Glossary: F-number

September 18th, 2008 by Greg

The F-number assigned to the camera lens indicates the brightness of the lens or the maximum amount of light the lens can direct to the camera’s image sensor. Both the maximum aperture size and the focal length of the lens play an important part in determining the F-number.

Iris and Focal Length

The maximum aperture size is self explanatory. The larger the iris opening (aperture) at its widest point, the more light will pass through to the sensor. When considering focal length, a lens will direct more light to the sensor with a short focal length (wide angle) as there is more of the physical scene captured by the lens to generate more light. Using a long focal length provides a magnified view of the physical scene and because the amount of the scene which is physically captured is reduced then less light from the scene is captured. Technically the F-number is worked out by the focal length divided by the maximum aperture or:

F-number = f (focal length)/D (maximum iris opening)

Simply put, the smaller the F-number of a lens, the greater amount of light is passed through to the sensor meaning that the camera will provide better picture quality in low-light conditions.

Glossary: Progressive Scan

September 17th, 2008 by Greg

Progressive scan is a technology associated with an IP camera’s imaging sensor and is used when transmitting, displaying or storing moving images.

Traditionally, the scanning method used in the majority of video signal formats has been interlace, used in such devices such as analog CCTV cameras, some CRT-based computer monitors and standard-definition televisions. Originally this was introduced as a way to overcome the bandwidth limitations of analogue broadcast infrastructure such as our NTSC or PAL SDTV signals.


Glossary: High Power PoE (IEEE802.3at)

September 16th, 2008 by Greg

Power over Ethernet (PoE) is a technology which allows IP cameras to be powered using the same standard Ethernet cable which carries the data connection.

The IEEE802.3af PoE regulated standard provides power up to 15.4W. This will cover the majority of static network cameras or fixed dome IP cameras but outdoor security cameras with built in heaters or pan-tilt-zoom (PTZ)/dome cameras normally have a power consumption which exceeds this.