YHGfL - Making the most of your broadband
What is VC?
Introduction
The impact of technology on schools has been increasing year by year and shows little sign of slowing. As the various technologies have converged in a digital platform, the communication potential of ICT has expanded dramatically. School students of all ages are embracing the digital revolution in the games they play and the text messages they send to each other’s mobile phones. Harnessing the newest technology to support their learning in schools is a challenge to which schools must now rise.
Video conferencing systems have been around for many years, but recent advances in technology now mean they are easy to use and have better quality picture and sound, so the video conferencing experience is much improved for all users.
Imagine that you are a Key Stage 3 history teacher looking at England, 1066 - 1500. As part of a lesson on the Normans you link via video conference to the Public Record Office where actors take on the characters of a Norman and a Saxon and re-enact an encounter over taxation. Your pupils are able to question and challenge the characters and see artefacts, including a facsimile of the Domesday book.
Imagine that you are a Key Stage 2 science teacher. You are studying the topic 'The Earth and Beyond'. You link your class via video conference to NASA, where experts lead your pupils in a discussion on living in space and link to astronauts in the space station, who answer questions from your pupils.
Imagine that you are a Year 6 pupil who wants to find out more about living in France and practise speaking French. Groups of children from a school in Exeter do just that every lunchtime when they link up with a primary school in Brittany.
Video conferencing offers enormous potential for enriching children's learning in ways that cannot easily be achieved by other means. It can radically alter the way children interact with one another and with the world outside the classroom walls.
What is Video Conferencing?
Video conferencing (VC) enables two or more individuals in different locations to talk to and see each other. VC sessions can also offer a medium for exchanging audio, image, video or any other type of digital file, enabling users to share computer applications and even work concurrently on a single file.
Although new technological developments are blurring distinctions, there are basically three types of VC system available.
Desktop units
Desktop video conferencing (DVC) entails users calling other individuals via their own computer. Instead of the traditional VC studio/room set-up where each person has a monitor for each site, DVC uses one on-screen window for each site. However, DVC has the following disadvantages:
• Transmission quality is lower than in other VC systems
• Poor sound quality means personal microphones or headsets are often required
• DVC software is currently complicated to configure
• There is an incompatibility between some systems
• Equipment costs are high.
Roll-abouts
Roll-about systems are complete VC packages housed within a wheeled cabinet. Although they are more expensive than desktop systems, the quality is usually better and they can use ISDN technology. They often have:
• one or two monitors on top of the cabinet
• at least one camera
• an audio system, including an echo canceller to handle audio feedback
• an audio suppresser unit to deal with background noise
• a control system
• a CODEC system to compress and decompress the audio and video signals.
Studio/room systems
Studio/room systems include all the equipment in a roll-about but form a permanent or semi-permanent installation. Since the equipment is fixed in a dedicated space, advance booking of the system is usually necessary and it can be hard to conduct a spontaneous session. Despite being the most expensive option, studio/room systems have higher audio and video quality than DVC and, in many cases, than roll-abouts.
Video conferencing connections
The quality of a VC session depends on how much information flows to and from each participating VC system and how fast it travels. There are three ways of connecting VC units and transmitting VC data:
• Over the Internet, an analogue telephone line with a modem or a digital ISDN line
• Over a local area network (LAN) or wide area network (WAN) within an institution, with, if required, an external connection via the Internet, telephone line or ISDN as above
• Over dedicated cables, radio or microwaves
Internet connection quality is not yet good enough to be relied on for teaching and learning due to the varying bandwidths through which the transmission may have to travel between the VC points, although this may well change as the technology improves.
Most long-distance VC occurs over digital phone lines and ISDN is emerging as the most commonly used communications method for desktop systems.
Some suppliers offer a mixture of digital ISDN, LAN/WAN and other connectivity, depending on what resources an institution already has and what it can afford.
Multipoint video conferencing
Many VC systems connect two sites together, but it is possible to have conferences between three or more sites. This is known as multipoint video conferencing and requires additional hardware/software called a multipoint control unit (MCU) or bridge. The MCU can be either situated in-house or on the premises of a third party, such as a VC service provider.
The Learning and Teaching Scotland Video Conference Hub (VC Hub) allows up to 12 parties to multipoint video conference at one time. This gives schools across the UK the opportunity to explore the potential benefits of interaction. The VC Hub can be used for foreign language teaching, signing video conferencing for deaf children or for management meetings.
How to choose a Video Conferencing System
Successful video conferencing takes careful project management with a sound business case and an astute choice of both equipment and retailer. This guidance is designed to help you choose a system that will meet your needs.
Selecting your bandwidth
As a rough measure, video-conferencing (VC) equipment can be priced according to the bandwidth at which it operates and the quality of its data compression. Imagine water travelling along a pipe. The wider the pipe (or broader the bandwidth), the more water (or VC picture and sound data) that can travel along it per second. VC equipment compresses the data so that more can be transmitted each second.
Internet or webcam using 24Kb or 56Kb modem
These are available from computer shops and high street stores for £50-£100. The small and jerky picture (quarter screen) with ability to transmit still pictures makes it recommended for home use only. It has the advantage of bringing friends and relatives together nationally or internationally for the price of a local telephone call.
ISDN2 (128Kb/sec)
Digital telephone lines such as ISDN2 or BT Home Highway (a conversion from the original analogue telephone line installed in homes) have long been the staple diet for video conferencing. At this bandwidth, a good steady picture can be produced on a TV or computer monitor. Expensive VC equipment can enable the picture to be enlarged to plasma screen or by projector, but here ISDN2 would be a false economy. Ideal use would be for daily conferences between colleagues who know each other. It is not recommended for initial job interviews or stressful sessions where decisions need to be based upon judgement of personal reactions and non-verbal or body signals.
ISDN6 (384Kb/sec)
The available bandwidth means that two large TV monitors can be used: one showing the participants at the 'other' end, and one to show the near end or electronic presentations such as PowerPoint or Flash. This is suitable for boardroom meetings, job interviews and situations where good co-ordination of picture and sound are essential for judging body language and response.
ISDN8 (512Kb/sec) and beyond
This high-end specification comes at a price. The BBC and ITV use VC running at 2Mb/sec via satellite links for carrying out real-time interviews in news programmes. The use of schools broadband may make high bandwidth a possibility for internal use, although price may be a restricting factor.
PC or Codec?
VC equipment is available in two types: as software loaded into a PC or as a CODEC, a purpose-built computer not dissimilar in size and appearance to a video recorder. PCs may be more convenient but CODEC-based equipment is easier to use and presents fewer technical difficulties.
Peripherals
Enhancements may be made to basic video-conferencing systems, depending upon the type and quality of the main equipment:
A camera that moves, pans and tilts, and enables preset positions to be selected, can enrich the quality of a meeting. Using camera presets, individuals or groups can be featured at the press of a button, or a whiteboard can be used to display text or maps.
Document cameras enable still pictures of 2D or 3D items to be transmitted.
Electronic whiteboards allow two locations to work collaboratively on a piece of work.
PCs or laptops may be connected to the system, to enable presentations or collaborative working via Netmeeting software.
A video recorder can be connected to the system, making it possible to record video from the 'other' end and sound from both ends. Video can also be played over the system.
The choice of medium
Traditionally, ISDN has been used for video conferencing. Modern VC equipment can use local or wide area networks. This presents no problem for broadband users, but 10/100Mb Ethernet users will need to consult their network managers before purchase if conflicts over system resources are to be avoided.
Deciding upon personal needs
How much do you have to spend? Remember that a case for funding, properly prepared and executed, will enable you to recover much of the equipment cost in a reasonably short time.
What do you want to do with the equipment? High-quality ISDN6 equipment can be used at lower bandwidth thus enabling economy, but ISDN2 cannot be used at a higher bandwidth.
Seek the advice of an existing user or a consultant. A retailer may not be able to provide the independent advice you need.
Obtain a realistic estimate of ISDN installation and call charges, as these may represent a substantial part of the purchasing budget.
Security and Child Protection Issues
As with the use of the Internet or email there is a number of technical and child protection issues that need to be considered. Whilst technically schools will want to protect their systems from hackers and viruses it is the need to protect children from unauthorised communication that is of paramount importance. This sort of communication could equally be initiated from within school as much as from outside.
Physical Security of the Video Conferencing System
Consideration must be given to the location AND setup of the video conferencing unit:
• Can it be locked away when not in use?
• Can it be password protected to prevent unauthorised use?
• Have the administration utilities been password protected?
• Is the system set to auto-answer? This can be a problem if the system is left on but with TV/Monitor switched off so that someone could dial in and eavesdrop unnoticed.
• Are unauthorised users prevented from making ISDN calls and running up large bills?
Network Security (IP video conferencing)
Many schools using IP-based conferencing will be connected to an LEA or RBC network. The LEA or RBC will have put in place Firewall and possibly Gatekeeper systems to protect the network and prevent unauthorised establishment of conferences by users outside the school, LEA or RBC.
It should be noted that many setups will register an end-point as soon as it is switched on; this could allow another school or user to connect straight in without pre-arrangement. Whilst this may be acceptable in some circumstances it does open up the possibility of eavesdropping as discussed above. All users must be made aware of the potential risks involved.
Schools should be aware that systems connected directly to the public Internet are particularly vulnerable because of the lack of external security systems. The use of public ILS servers to establish calls is also a potential hazard because the school system is registered and available publicly for connection by any Internet user.