| The simplest form of videoconferencing is a | | | | all times, much like the television show |
| point-to-point call, one person contacting | | | | Hollywood Squares. |
| another person via the Internet. This basic | | | | |
| level of videoconferencing is similar to | | | | Interesting as Continuous Presence is, it is |
| making a phone call with a picture phone. | | | | not the default mode for multipoint |
| Multipoint videoconferencing occurs when | | | | videoconferencing. The default mode is |
| three or more locations connect | | | | Voice-Activated Switching, or VAS. In VAS a |
| simultaneously, much like a three-way phone | | | | multitude of sites are connected and the |
| conversation only the logistics are much more | | | | person all views speaking. This should bring |
| complex. | | | | to mind the image of a newscaster or |
| | | | spokesperson on standard television. |
| To begin understanding the complexity of | | | | |
| multipoint conferencing one must enter the | | | | An important point in the VAS mode is that |
| domain of technology and begin with ISDN. | | | | although the transmission focus will be on |
| ISDN means simply Standards for Integrated | | | | the one who is speaking, anyone and everyone |
| Services Digital Network, a high quality, | | | | connected to the videoconference can change |
| switched digital communications service that | | | | the view. Remember the term is |
| gives your standard phone line the ability to | | | | voice-activated. If someone coughs or |
| transmit voice and data simultaneously. | | | | sneezes, the camera recognizes them. In VAS |
| | | | multipoint videoconferencing it is very |
| You can use the same line for regular | | | | important to mute your microphone until it is |
| telephone service, faxing, computer | | | | your turn to speak. |
| communication, or even live videoconferences. | | | | |
| Each of these applications requires suitably | | | | There are yet other modes of transmission for |
| equipped customer-provided equipment. ISDN | | | | a multipoint videoconference. These are Chair |
| transmissions are significantly faster than | | | | Control, Lecture Mode, and Broadcast with |
| using a modem. Think of ISDN as a high-tech | | | | Autoscan. In Chair Control and Lecture Mode |
| phone line. | | | | the presenter is seen full-screen by all |
| | | | sites at all times, even if a speaker at |
| The next essential ingredient in a multipoint | | | | another site speaks. This mode is used |
| conference is the bridge. This is a | | | | primarily with distance learning, when the |
| multipoint control unit known as MCU, the | | | | situation requires that students always see |
| component that manages the videoconferences | | | | the presenter rather than speakers at other |
| when of three or more participants are | | | | remote sites. |
| involved. | | | | |
| | | | Broadcast with Autoscan means only the |
| An MCU can support some or all of the | | | | director or presenter is able to view all the |
| following: audio-only calls, video calls at | | | | remote sites while the remote sites can see |
| various video bandwidths, video calls, data | | | | the video that is being broadcast. This |
| sharing, continuous presence, cascaded calls, | | | | becomes even closer to a television broadcast |
| a conference call web page and component | | | | via the Internet. This mode is preferred for |
| stacking. Component stacking can remain in | | | | videoconference presentations and seminars, |
| the technicians domain but continuous | | | | when audience response is not anticipated or |
| presence deserves attention by anyone who | | | | required and unlike a television broadcast, a |
| would understand multipoint | | | | multipoint videoconference in broadcast with |
| videoconferencing. | | | | Autoscan mode allows the director or |
| | | | presenter to view the audience and watch for |
| Continuous presence, also know as the CP Mode | | | | response. |
| is when all sites in the videoconference can | | | | |
| be seen at the same time on the far end | | | | In todays computer world most multipoint |
| monitors. Those involved in the | | | | videoconferencing systems have built-in |
| videoconference will see themselves (or any | | | | bridges which allow you to connect to |
| data that they present) on their right hand | | | | multiple sites just as you would in a |
| monitor while at the same time they can see | | | | point-to-point call Even more advantageous is |
| themselves and everyone else on the screen. | | | | the rise in technology to include built-in |
| | | | gateways. A gateway is a network point acting |
| Continuous presence is often used when | | | | as an entrance to another network. This |
| presentation is required. As you can see, | | | | allows communication across any set of |
| multipoint videoconferencing with continuous | | | | interconnected networks. |
| presence activated can be very effective for | | | | |
| business or hospital transmission. Another | | | | This means the World-Wide-Web is now |
| way of looking at CP is seeing each site in a | | | | available for anyone interested in a |
| split screen format on the display monitor at | | | | multipoint videoconference. |