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Volume 3 Issue 1January 1999

TIPS on Videoconferencing
Multi-Point Conferencing

Mary Shrader Lasica
Education Advocate, Pacific Bell

This article will address the technology needed to accomplish a multi-point videoconference connection, the number of sites that can reasonably connect to a multi-point conference, communication strategies that can contribute to the success of the meeting or conference, and a few tips from experienced users.

What technology do I need to connect three or more sites?
Point-to-point videoconferences are made by one videoconference location directly dialing another, It is possible to videoconference (see and hear) with the other site because both sites are connected to the telephone network by way of a special digital phone line. After dialing and connecting to the other site, the far end (the location that has been called) will appear in the main frame of the monitor. The local site will appear in either the PIP (picture-in-picture) or on the second monitor.

To connect three or more videoconference units into a single call, it is necessary to use a multi-point video bridge. This bridge allows each participating videoconference location to dial into the bridge equipment using a number assigned by the bridge scheduler. What will appear when the site is connected will depend on the capabilities of the bridge itself.

A voice-activated bridge will allow the different sites to see and hear the site currently speaking or presenting. A question from another site will cause the picture to switch to that site. The local site can be viewed on the PIP or second monitor.

A continuous-presence bridge will arrange the video images of the locations in four boxes on the monitor (think of the opening credits of the Brady Bunch). These three or four sites will be viewed continuously throughout the videoconference. Generally, four sites in view are the limit for these conferences; however, more sites can join as viewers, rather than full participants who can be both seen and heard. A new option on certain bridges allows one of the quadrants (or squares) to be "voice-activated" so all sites can be seen and heard.

The California Community College Chancellor’s Office (CCCCO) has a bridge provided by PictureTel. This bridge has continuous presence capabilities. To learn more about the bridge and the procedure for reserving the bridge, consult the Videoconferencing page on the CCCCO web site at http://www.cccco.edu/ESED/irt/tnt/video/cccco.html.

For videoconference planners at sites that are not in the California Community College system, bridge services are available from a variety of different vendors. To find out more, visit the multi-point page on Pacific Bell’s Videoconferencing for Learning: http://www.kn.pacbell.com/wired/vidconf/multipoint.html . Costs include rental of the bridge (usually charged by the hour) and any long-distance charges incurred while dialing into the bridge.

How many sites can dial into the bridge for a multi-point conference?
The type of videoconferencing units purchased by California Community Colleges are designed for maximum communication and interaction between sites, so that different locations can clearly see and hear the other locations to whom they are connected. Every time another location is added to the videoconference, however, there is an increased layer of complexity both to the technology that allows all locations to see and hear each other, and to the quality of the communication itself. As more sites are added, it becomes more difficult for all sites to participate fully.

Connecting more than three or four locations will limit the interactive nature of videoconferencing. It is possible to connect more than four sites together on many types of bridges. For example, one location might wish to simply broadcast information rather than interact from location to location. Keep in mind that the complexity of the technology increases with each location added.

What communication strategies work best in a multi-point videoconference?
Think of strategies that might be employed when planning a meeting for fifty people or more. These strategies are similar for multi-point conferences. Meetings for smaller numbers of participants can be much more informal. Larger meetings need more structure as well as a facilitator.

Appoint a facilitator who has previously used videoconferencing to manage an agenda and communication between locations. The facilitator can plan the agenda so that presentations will be from different locations; the "action" can move from site to site. The agenda should also leave time for questions and answers from different sites.

When questions are allowed, plan which location will ask the first questions, which location will go next. Keep this order consistent throughout the videoconference. The facilitator can explain the order at the start of the conference, then when questions are allowed, prompt each site with "Location A, are there any questions?"

When a speaker is presenting at a distant site, all other locations should mute their microphones. This is extremely important! The microphones used by the PictureTel videoconferencing units are very sensitive, and can transmit muffled comments, the sound of sneezing or rustling papers; when using a voice-activated bridge, the camera will then be viewing the interruption, rather than the main speaker.

Be sure the camera is pointed toward the person speaking before proceeding with the presentation, question, or comment. Especially for those asking questions, begin with "I’d like to ask a question" and pause until the camera is focused on the person asking the question. Then, proceed with the question or comment.

What else do I need to know?
When connecting to videoconferencing units at California Community Colleges manufactured by PictureTel, use H.320 standards at a connection rate of 384 kbps. This will give a clear sound and a clear video image that will be refreshed between 22-25 frames per second.

When connecting to locations outside of the community college network, be sure that each location can connect to the bridge using H.320 standards. Ascertain their ability to connect to a bridge at a particular rate, as some sites may only have the ability to connect at 128 kbps. Decide if all locations will connect at the lower rate (which will affect the quality of the video images all sites see) or if those participants should travel to a location with videoconferencing equipment that connects at a higher rate. (Some bridging services allow sites to participate at different rates, so this might be another option.)

Reserve the video bridge for one hour prior to the start of the meeting (to allow all sites to get connected before the meeting actually begins) and 30 minutes following the time set for the conclusion of the meeting (to make sure you are not cut off in mid-sentence).

Set up a test call the day before the actual meeting so that all sites can test their ability to dial into the bridge and see and hear all participants. Allow at least a ninety-minute test call to resolve all technological issues one day prior to the meeting. If the correct information was not given to those programming the bridge, some locations may not be able to see or hear other locations. The bridge may need to be reset, and all locations will need to connect to the bridge again. During this test videoconference, audio and video can be checked, and equip-ment, such as fans for air conditioning units, can be adjusted.

Finally, on the day of the meeting, connect to the bridge at least 60 minutes prior to the start of the meeting. Allow time to resolve any new issues that might arise.

Multi-point videoconferencing is a wonderful tool to allow you to meet with colleagues across the state and the country. With the help of the videoconference support staff at each college, you can be part of a team that works constantly to improve the uses of the technology available for you and your community. To find out more about multi-point videoconferencing in classroom situations, visit Pacific Bell Videoconferencing for Learning at http://www.kn.pacbell.com/wired/vidconf/multipoint.html.

Contact:
Mary Schrader Lasica
Education Advocate
Pacific Bell
mxlasic@pacbell.com