In this article we take a look at the basic types of IP Surveillance Cameras. We would also discuss some of the salient features of IP Surveillance cameras as well as IP PTZ Surveillance cameras to see how they enhance video surveillance.

Types of IP Surveillance Cameras:

There are basically four types of IP Surveillance cameras: Fixed, Fixed Dome, PTZ and PTZ Dome.

In Fixed cameras the viewing angle is fixed and it is permanently mounted to cover a certain area always. The camera and its direction of coverage is also pretty visible to everyone and the lenses might be easily changeable. For outdoor applications, they might have to be kept within some kind of protective housing.

With Fixed Dome cameras, the cameras are fixed in a small dome type housing to cover a certain area always. But due to the dome enclosure, it is hard to see in which direction the camera is pointing and it is hard to tamper with such cameras and they are also weather resistant and hence suitable for outdoor applications without requiring additional protective housing. However, the number of lenses that can be attached with them is limited based on the size of the dome.

A PTZ Camera refers to Pan Tilt and Zoom Camera where the camera’s view can be remotely controlled either manually or automatically for tilting up and down, panning side to side and zooming in and out. An operator can for instance follow a person along the road by rotating the camera up, down, sideways and zooming on them as required.

A PTZ dome camera is also a PTZ camera, but it is kept inside a dome. These PTZ dome cameras have a full 360 degree Pan and they can continuously move between preset positions (which are already stored) to monitor multiple angles/areas one by one in a particular sequence.

There are also Non-Mechanical PTZ cameras which has a wide angle lens (sometimes more than 180 degrees) and can zoom in to any part of the image without mechanical movement but by using optics alone. But here, the pan,tilt and zoom actions are limited.

Salient Features of IP/PTZ Surveillance Cameras:

Auto Focus: The auto focus feature of IP Surveillance cameras that can be zoomed could be handy when working with PTZ IP Cameras.

Night Vision: Many IP Surveillance cameras support night vision by turning off the IR Filter which makes the image viewable at night, in black and white.

White balance: Some IP Surveillance cameras can identify the light source used and compensate for its colour which is useful to reflect the natural colours.

Bandwidth Limiting: Certain IP Surveillance cameras can limit the bit rate at which the images are sent via the network and hence controlling the network bandwidth that is required to transmit the captured video images of the IP Cameras. But there might be some loss in image quality due to this.

Freeze: Images can be freezed during the pan, tilt and zoom operations (for PTZ Camera) and the current image can be shown after the camera has reached its position.

Back-light compensation: This feature makes the focused objects look more clear against a bright background.

Audio: Some IP Cameras allow for recording the voice along with video (external microphone connectivity is provided in the cameras). With some models, a full duplex voice communication is possible which enables to transmit and receive audio like a telephone conversation.

Camera Preset Positions: Many IP PTZ Surveillance cameras allow for setting pre-set camera viewing angle/zoom positions which can be accessed with a single click, later. The camera can also move through the selected pre-set positions in set order or at random.

360 Degree View: Certain PTZ cameras support continuous 360 degree rotation for coverage. Even if there is a mechanical stop in between, the camera can exhibit continuous Pan movement in the same direction by reversing the camera lens and slipping it over when the camera reaches the mechanical stop.

Motion Detection: This feature is used to generate an alarm whenever movement occurs (or stops) in the image. There are certain include windows which can target specific areas within the images and there are certain exclude windows which can ignore specific areas for motion detection. Motion detection may not function which the camera lens is moving.

Interchangeable components: Some IP Surveillance cameras provide interchangeable components (including the CPU, power supply, cameras etc) and individual components can be replaced/changed at any time. This helps rectify faults and there is also no need to change the whole camera when the CPU becomes obsolete, for example.

Analog connectivity: Some IP Surveillance cameras come with an optional analog connectivity which can also connect to the co-axial cable network in addition to the IP network. Analog surveillance cameras can be connected to the IP network using Video encoders.

Privacy Masks: IP Surveillance cameras allow to block/blur certain parts of the screen using privacy masks. In fact, multiple privacy masks can be deployed in the same scene. In some IP Cameras, these privacy masks increase their size automatically, when the image is zoomed in.

Recorded Tour: Some IP Cameras allow the recording of the movements of the operator (pan, zoom included) and the same can be played back later.

Alarms: If any unwanted incidents happen with the cameras like cutting the cables etc. that can stop the functioning of the IP cameras, certain alarms can be activated by them based on the event and severity. These alarms can range from sending emails, SMS to activating an external device automatically through input/output ports available in the cameras.

Simultaneous streaming of multiple formats: Certain IP surveillance cameras support the streaming of multiple compression formats (like Motion JPEG, MPEG 4), frame rates, resolutions etc. simultaneously to multiple devices for optimum performance.

Auto-tracking: Some IP Cameras support auto-tracking of images where Pan and Tilt can be automatically controlled by the camera to follow moving objects by centring them in the screen.

Power Over Ethernet (POE): Many IP surveillance cameras support POE – Power Over Ethernet feature which lets the network data cable (Cat 5E/6) to carry both power and data simultaneously without having to carry a separate power cable to the cameras.

Wireless: Some IP surveillance cameras support wireless connectivity to networks/access points through IEEE 802 wireless standards.This can be useful in cases where the data cables cannot be taken/very expensive to be taken till the IP cameras.

API: Some IP Surveillance cameras give an open standards based Application Programming Interface that enables many software vendors to write programs for specific applications using the IP Cameras.

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This article gives an idea about how the video encoders help use existing analog cameras and analog (coaxial) cables and still migrate to an IP platform for Video Surveillance. We also discuss the features supported by such video encoders.

Video surveillance has traditionally been handled through analog video cameras, analog coaxial cable network and a DVR/recording-playback central device with monitors to view the output. But of late, IP surveillance systems (IP Cameras, IP Cat 5E/6 network cables and computer servers/video management software’s) have started to become more popular due to many advantages of IP Video surveillance.

But since many companies/organizations have huge investments on the existing analog surveillance cameras and also on the analog coaxial cable network. To change to an IP Video surveillance system means to discard all these analog components. Not many are aware of Video Encoders which can be used (as a temporary measure, if required) to migrate to IP Video surveillance by retaining the investments on the existing analog cameras and the analog network.

What is a Video Encoder?

Video Encoders (also called video servers) connect to analog cameras via coaxial cables at one end and an IP network via RJ-45 jacks and Cat5E/6 cables at the other end. They are introduced (possibly near the analog cameras) to convert the analog video produced by the analog CCTV cameras into digital video streams that are sent over the IP network. So, it basically helps to build an IP based video surveillance systems (with many of its advantages) by retaining the existing analog CCTV cameras and coaxial cables (to a certain extant). Video encoders support a single camera as well as multiple cameras, based on the model. The cost advantage of not having to replace all the analog cameras with IP cameras is the primary goal of introducing such an intermediate device but the compatibility of the existing cameras etc. needs to be checked with the vendors before investing in them, but many types of analog cameras (like fixed, PTZ, dome etc.) can be connected to the video encoder. Such video encoders can support a lot of features of IP video surveillance using analog cameras and a short list is given below.

Salient Features supported by Video Encoders:

¤ The analog cameras can be controlled from remote location over the IP network and the video encoders.

¤ Certain video encoders support PoE (Power Over Ethernet) standard which lets them to be powered via the Cat5E/6 cables which carry power along with data. So, a separate power cable may not be required.

¤ Video encoders introduce intelligence into the surveillance by enabling features like video motion detection and a few even support audio detection. This is useful when playing back the video images where only the scenes where some motion was detected could be looked at. Or, recording of the video can be limited to only those scenes where some motion or sound is detected.

¤ They enable alarms to be generated based on certain events (like cutting off the cables to the cameras etc.). These alarms could be simple email alerts, starting video recording etc. and also complex actions like activating a siren/closing doors automatically etc. Such actions can be possible by connecting external sensors and relays through the I/O connections present in the video encoders.

¤ The video encoders support high frame rates (like 25/30 fps) and multiple resolutions like CIF, 4CIF etc. They also support more than one compression formats simultaneously – like MPEG4, H.264 etc.

¤ Some of them correct the aspect ratios obtained by the analog capture to suit the viewing on a PC screen.

¤ Video encoders can provide multiple video streams simultaneously and each stream can be configured with different compression formats, resolution and frame rates.

¤ Based on the vendor, video encoders support video management softwares which allow for central control of recording, monitoring, playback and management capabilities.

¤ Once the video is converted in to the IP format, many IP network security systems like encryption, authentication (802.1x etc) are supported by video encoders.

¤ Some video encoders also support network QoS reservation parameters for optimum quality of video playback.

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This article gives an introduction to Telepresence, how Telepresence creates an immersive real time meeting atmosphere, what are the components of Telepresence, interoperability between Telepresence and video conferencing and bandwidth requirements of a Telepresence solution.

Picture Courtesy -  http://www.flickr.com/people/smartcities/

What is Telepresence?

Telepresence is a combination of a number of high quality audio, HD video, content collaboration tools, lighting, conference tables and chairs, huge multiple display devices etc. which enable the participants to see and talk to remote locations, as if they were in the same room, sharing the same table. An example of telepresence is shown in the picture above.

How Telepresence creates an immersive real-time meeting atmosphere:

Telepresence is about creating the “Same Room” experience to all the participants. That comes from a number of factors.

High quality audio: Telepresence creates a feel as if the person in the remote site is actually talking to you from the same room. Multi-channel audio can provide directional cues as to who is speaking by enabling the sound from a particular speaker in the remote site come from a particular direction (from the location where the monitor displaying them is present, for example). In addition to this, the audio is clear, audible and echo-free.

High quality video: Video is displayed in big display units (like three 65″ LCD monitors which can display life size display of the remote participant as in the above picture) and create a feel of seeing and speaking to them in real time. The size, eye synchronization etc. of the remote participants are ensured to be similar to the experience, if they were in the same room. For this, the three different cameras are placed just over the LCD monitors, each focusing a different part of a room and creating a unified image in a similar set up in the remote location.

Immersive Environment: Telepresence is more than just audio and video: It creates a whole similar environment in multiple sites to create a feel as if they were in the same room. So, the furniture – conference room tables, chairs, wall paint colour, fixtures, lighting etc. are similar in all the locations. Even the table is arranged in such a way that user can see one half of the table in his room, and the other half on the monitor to create an illusion that all of them are in the same room.

Simplicity: Most of the Telepresence systems are perfectly pre-configured (for a particular number of participants from each side) and do not require the participants to touch any of the settings, perhaps other than the “On” button. In fact, many features of the video conferencing systems like zooming, rotating the camera etc. are disallowed in Telepresence so that the immersive real time feel does not get altered. Even the collaboration is enabled through simple touch screen monitors on the table which displays the content that is shared from the other side.

Components of a Telepresence solution:

A Telepresence solution like the one shown in the picture above would be requiring the following components: 3 x 60″/ 65″ Full HD LCD Displays, 3 x HD Video Conferencing/Telepresence Codecs. 3 x HD 1080p Cameras, 3 x Speaker modules, 6 x directional microphones, integrated table, ceiling mounted studio lighting modules, similar chairs and optional three units of LCD touchscreen displays for content presentation. Only the basic components of one type of Telepresence are displayed here, for your understanding. There are certain Telepresence solutions that display much more people in a meeting hall set up with rear projection LCD Screens etc, and there the configuration may be entirely different.

Interoperability between Telepresence and Video Conferencing:

Telepresence, at its heart is the collaboration between multiple HD Video Conferencing systems. So, a Telepresence call can be set up between a Telepresence unit and video conferencing system (multiple of them, in different combinations) and even multi party conferences can be set up. The picture in this article is displaying a session between a video conferencing unit and Telepresence system and hence only the middle display is occupied. If the call was between two or multiple Telepresence systems, all the three displays would have been occupied.

Bandwidth requirements for Telepresence systems:

While HD Video Conferencing systems might require in addition to 1.5 Mbps per site, Telepresence systems may require about 15 to 20 Mbps of bandwidth per site.

So, as you can see from the above description, Telepresence systems are quite expensive but they seek to create an immersive “same room” experience which might be critical for certain applications. Perhaps organizations could first experience the managed Telepresence solutions (where the whole set up is available for rent) before going in for their own set up.

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This article discusses the components of a Video Surveillance system and how digital functionality is enabled by IP Video Surveillance system by digitizing all the components of a Video surveillance system namely – camera, recording, monitor and network.

A video surveillance system consists of four components – Camera, recording, monitor and video network. The CCTV/DVR systems which were employed earlier used the CCD Cameras to record the video which is converted in to analog form for transmission over the co-axial cables and then again digitized in the DVR (Digital Video Recorder) for compression and recording. So, this multiple conversion system (just to carry the video signals over the Co-axial cable) was quite inefficient especially when the digital video signal was converted in to analog signal then back again to digital signal. That’s where the IP Surveillance system comes in to the picture which enables the entire process to be digitized completely. We will take a look at how it is done at the individual component level:

Camera: What was the analog tube camera, was replaced by the digital CCD cameras which generated the image in digital format. Even though the output of a CCD camera was digital, it needed to be converted in to analog for carrying it over the co-axial cable in the component video format. So, these CCD cameras did this conversion. The CCD cameras are replaced by IP Cameras which generates digital video and allows the digital video to be transmitted over the IP network without conversion.

Recording: The analog VCR Tapes of the earlier era was replaced by the DVR – Digital Video Recorder. This was generally a proprietary hardware device which received the analog signals from co-axial cables, digitized it, compressed it and recorded it over disks (which made archiving and searching easier). These Digital Video Recorders (DVR) are replaced by Network Video Recorder (NVR) which receive digital video input from an IP network and record them using recording software’s over any standard computer server.

Monitor: The monitor, which is used to display the video for surveillance, was earlier CRT based. This was converted in to a PC based monitor with DVR. Now, it remains a computer monitor/LCD Display unit and accepts video input directly from a Network Video Recorder (NVR) for displaying the digitized video.

Network: The video network, which was formed using co-axial cables to carry the video signals in analog format is now changed to IP Network which uses twisted pair cables – Catx based, which enables to carry the video signals using digital format. The IP Network, which is already available in most organizations for carrying data can be used with some additions or a new IP network using switches, IP cameras, Catx cables can be created – which could still be less expensive than the analog co-axial cable network. The IP network also enables remote monitoring and control of the IP Video Surveillance system (like over the internet etc). Even the wireless network can be used to connect to the IP Cameras in remote locations or even everywhere to create a total wireless video surveillance system in the campus. This is possible because of the IP Network being employed to carry the digital video signals.

The fundamental difference between a DVR and IP Surveillance concepts:

In a DVR(Digital Video Recorder), the process of digitization and compression of video signals occur in the recorder unit while in the NVR(Network Video Recorder for IP Surveillance), the digitization and compression of video signals occur in the IP Cameras. That enables the IP Cameras to provide intelligent functionalities like motion sensing etc. which partly explains the higher cost of the IP Surveillance Cameras. But the advantages of IP Surveillance are many including scalability, redundancy, single network, additional functionalities etc.

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Related Reading: Types and Features of IP/PTZ Surveillance Cameras

This article is to provide an overview of audio conferencing systems, their features, cell phone connectivity, integration with video conference, content sharing on an audio conference and audio conference systems over IP.

What is an audio conferencing system?

An audio conferencing unit is generally a triangle shaped phone unit which has three microphones and one speaker and connects to a telephone line or PBX trunk line to make and receive external calls. The users can sit around the audio conference system and talk to the other end. It is like a sophisticated speaker phone and can do much more than a speaker phone including providing a higher distance coverage and better quality.

Features of an audio conferencing system:

Entry level models have a coverage of up to 10 feet from the audio conference system – meaning multiple users from one side can talk to multiple users in remote side through a phone line and talk to them as long as they are within a 10 feet radius from the audio conference unit. Generally they provide full duplex speech capabilities. Some of them also come with a back-lit display to display the phone numbers, caller ID, call duration etc. They have most of the normal buttons found on the phones like redial, mute, transfer, hold etc. Some systems allow the connection of additional microphones for covering more area. Some advanced models also cover up to 20 feet, support HD voice and even support an optional sub-woofer to amplify the low level sounds for good clarity.

Cell phone connectivity to an audio conferencing system:

Some audio conferencing units allow to dial out or receive calls for having an audio conference through a cell phone. You need to connect the audio conference unit to the headset jack of the cell phone. This provides two functionalities: The use of the audio conference unit as a hands free unit for individual calls, and also conducting audio conferences using the cell phone network instead of the POTS trunk line as some conference rooms may not have a telephone trunk line coming in. The voice in such systems are generally encrypted for safety and an optional RJ-11 connectivity is also present to connect the analog trunk line. They may also come with a battery charger so that the whole system can be used in a wireless way and anywhere a cellphone network coverage is present.

Connectivity to a Video Conference:

Most of the video conference systems allow taking audio users as a part of the video conference session. So, the users of the video conference can talk to a remote site using only audio or both video and audio (if a VC system is present). Even a single cell phone user can be added to such a video conference session but an audio conferencing system enables a group of people to be added to it. Some advanced models integrate with the video conferencing units and allow the video conference users to dial to other video conferencing systems using the buttons of the audio conference users. It also becomes an additional microphone for the video conference users, in that case.

Content Sharing and Collaboration:

There are certain systems which allow users to share their content along with the audio conference session. There are certain specialized units that allow the users to connect the audio conferencing unit, LCD projector, Computer and internet connectivity to allow the collaboration of the audio conference session with content. Users connect their computers to this device using a VGA cable, dial the conference number and allow content sharing mode to share their presentations live while on the audio conference. The content can be displayed over the projector or a web browser. They actually set up a H.323 content sharing channel over the internet to transfer the content to remote site, live.

Audio Conferencing over IP:

There are certain IP Conference devices which gives most of the basic functions of an audio conferencing units discussed above but doesn’t connect over the analog telephone line. In fact, it connects over IP network to an IP PBX. Such phones are essentially SIP enabled for connecting to multi-vendor IP PBX. So, they register to the SIP enabled PBX as an IP device and an IP address gets assigned to them. So, in the future, there is no need to take a separate analog line in to your conference room to connect an audio conference unit.

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This article introduces the High Definition or HD Video Conferencing, the standards used in HD video conferencing with reference to definition(pixels) and presentation of motion(frames per second), advantages of HD video conferencing, aspect ratio and bandwidth in HD video conferencing and requirements of HD video conferencing.

What is High Definition (HD) Video Conferencing?

The older/some of current video conferencing is referred as SD or Standard Definition Video Conferencing.  This is popularly referred to as 480p format has a resolution of 860 x 480 and supports up to 30 frames per second of video in a 4:3 aspect ratio. So, when such video conferencing systems are connected to HD displays (supporting 16:9 aspect ratio), they would either introduce two black lines at the two edges to make to 4:3, or adjust the image to entire screen causing reduction of clarity.

With High Definition Video Conferencing systems, two popular formats are supported – 1080p with a resolution of 1920 x 1080 pixels or 720p with a resolution of 1280 x 720 pixels. Both the formats support direct 16:9 aspect ratio and hence making use of the entire screen of a high definition display.

The basic difference between the older SD technology and HD technology is the definition – HD supports a higher resolution (More resolution directly means more information and better quality) and they use a technique called progressive scanning in which every horizontal line of pixels are displayed from top to bottom, one after the other (compared to the older interlaced scanning by SD systems which alternates the horizontal lines for display, essentially refreshing the image before it can be displayed) and because of which it is twice as fast as the older SD technology. The presentation of motion which is displayed in terms of frames per second also enables the display of subtle changes in motion with a true 30 frames per second and 60 frames per second support.

High quality always comes with higher bandwidth. So, generally HD systems need a minimum about 1.5 Mbps of bandwidth to display crisp and sharp images. When compared to an SD system which could display images even at 128 kbps, this is quite high but the quality is far better.

Requirements for a High Definition Video Conferencing:

For an effective high definition video conference session to happen, the video conferencing units at both ends (or all ends) must be HD enabled. Well, there is not a huge price difference between a SD video conferencing and a HD video conferencing unit, so this may not be an issue. Also, the camera should be HD enabled. A minimum bandwidth of 1.5 Mbps is required over IP or PRI for effective HD video conferencing. The display unit(Like LCD, DLP, Plasma displays) should also support HD display and should have an aspect ratio of 16:9. These devices could be bigger in size (like 50″ diagonal) and still deliver a good clarity when compared to SD monitors which need to be less than 27″ diagonal and have a 4:3 aspect ratio for effective quality. A wide band audio support would also enhance the experience. It is suggested that even the document cameras (which help transmit the contents of a paper/brochure to the other side) is high definition enabled. It always helps to have set strict QoS parameters in your network for prioritising video traffic. The high definition display units should have HD connectors like DVI-I or YPrPb in order to connect to those ports of the video conference units. If an MCU (Multi Conference Unit) is used, even that needs to be HD enabled along with all the video conference units.On a related note, refer the following article for the bandwidth requirements and types of connectivity for normal video conferencing systems.

The advantages are obvious: Better quality video, ability to see crisp and clear images including eyeball movements, facial expressions etc, support for 16:9 resolution and bigger and effective display units, and the ability to view excel sheets, ppt slides and images, display boards etc. with a very high clarity.

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This article gives a small introduction to a Multi-Conference Unit in Video Conferencing systems, the necessity to have a separate hardware based multi-conferencing unit,  the features and functionalities supported by them, managed multi-conferencing systems, gateways and gatekeepers.

What is a Multi-Conference Unit?

To understand this, you ought to know what is a Point to Point Video Conferencing system. Basically, when you want to see and speak to someone who is far away, you could use a video conferencing system to have a live face to face meeting with them, of course sitting from your office. A VC system consists of a Codec (Processor, Interfaces for ISDN/IP etc.), Display Units (TV, LCD Monitor etc.), Camera (Generally attached with the codec, some are detachable), Microphones and Speakers. This systems ought to be there with the other person with whom you wish to communicate. It is not necessary that both are from the same manufacturer, as most of them follow standards and are very much interoperable.

These Video Conferencing codec’s allow you to do simple multi-party calls. You are in a conference with your regional office one, and you also want your regional office two to participate in the same conference (from a different place), you could dial both of them and have a simple multi-conference. Most of the codec’s support 4-Party Conference (including yours) or 5-Party Conference, with the basic unit itself. Now, what if you want to have a 12-Party conference? That’s what a multi-conference unit is for.

Features of a Multi-Conference Unit:

The MCU is a hardware unit and some of the bigger ones are Chassis based systems where the media, recording, gateway and interface units can be added via blades and may have redundant hot swappable fan units and power supplies. Any standard video conference system can connect to the MCU for multi-conference by dialling in, or scheduling a call from the MCU. Some MCU’s also support entry through a Video Auto-Attendant or Interactive Voice Response when an endpoint unit calls. Depending on the model, they support 12-Party, 24-Party end points, etc. The bigger ones can support a few hundred end points and they can be cascaded to support even more. Some vendors also support (may require additional hardware, blades) recording, archiving, streaming and playback of video sessions.

The endpoints can call an MCU on any of the following – H.320(ISDN), H.323(IP), SIP(Video Phones),HD(High Definition video). MCU supports Transcoding – The various video conference systems connecting to it can have different data rates, different audio or video algorithms, different standards, different frame rates, etc. The MCU can still negotiate the best possible connectivity with each of them. MCU can also support telepresence calls.

When so many sites are present in a single video conference session, it is vital that there are display options. MCU’s support flexible continuous presence where display layout is divided so that the speaker or main site is on the centre and the other sites are in small PIP displays in the bottom or/and sides. So, bigger displays are better to clearly view a large number of sites simultaneously or multiple displays can be arranged. Alternatively, only the site that is speaking can be displayed on the screen and other sites can be displayed when they start speaking. This can be done by a technique called voice activated camera switching. The best thing, if you want complete control is to take the chair control where you decide who is on the main screen – you might just want the HQ on the main screen always with the branches mostly listening.

Multi-Conference Service Providers:

The Multi-Conferencing facility can be procured on-demand (temporarily) from large service providers who invest in big MCU’s and extend hourly/no. of calls/no. of sites based billing systems. So, when a multi-conference call is required, you can book it with them and use their system to call you or your endpoints can call them to set up a Multi-Conference. Some providers also have their video conference booths where you can go and call other sites, if you don’t have a video conference end point or the bandwidth required for VC Sessions.

Gateways and Gatekeepers:

Gateways: It is a network device that allows H.323 (IP) based video conferencing units to connect to  H.320 (ISDN) based video conferencing units. The MCU’s might use this to provide multi protocol support. They have LAN ports as well as ISDN/PRI ports.

Gatekeepers: They provide addressing service for H.323(IP) based video conferencing units and optionally can also impose bandwidth restrictions. The addressing service is required for a video conference unit to dial another VC unit by using the video conference IP address (which is generally static). Otherwise, the IP address might be changed at the gateway (NAT/DHCP) and the receiving end video conference unit cannot identify who is calling.

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