Compared with just a few years ago teleconferencing is much more cost effective. Audio-conferencing can now be affordably fitted to almost every meeting room. Videoconferencing can be afforded by relatively small enterprises. But the range of options and considerations can be bewildering!

An audio-conferencing unit is more than just a speaker-phone. The basic units offer:

• 360° microphone sensitivity - this will usually require an array of two or three microphones.
• Acoustic echo suppression - without it, depending on communication delays, you can get:
• A disruptive repeat of your words coming back to you;
• Reverberation impacting intelligibility of speech; or
• Feedback howl
• Background noise suppression
• Dynamic range compression, boosting weaker voices
• Smaller units, 3 to 4 people, up to 2m away
• Bigger units, 10 to 12 people, up to 3m away.

Further options include:

• Wireless connectivity eg Bluetooth
• Extension microphones for long tables, more people
• Stereo / surround sound - speakers' voices come from the "right" direction - this will require a wall- or ceiling-mounted speaker array.
• Ceiling mounted microphone array
• Internet connectivity

At East Coast Audio Visual one of our AV consultants can guide you through your options.

Thanks to the availability of more affordable projectors, relatively cheap broadband and vastly improved compression techniques, video-conferencing is now within the reach of smaller enterprises. However, the results you get can vary wildly depending on configuration.

Firstly, on the audio side, all the considerations for audio-conferencing apply. In fact, some configurations simply use an audio-conferencing unit which integrates with a video solution.

For the video display, typically at XGA resolution (computer-based images) or PAL (TV-based images), choose between:

• LCD / Plasma
• Projector
• Rear projection

Room and audience size, lighting and contrast resolution all need to be considered in selecting the right video display.

Going up the scale are these sort of camera system options:

• Fixed camera generally on top of the display, or at the foot of the projection screen.
• Pan/tilt/zoom (PTZ) camera which can be controlled from the other end. PTZ cameras generally support a varying number of presets, which typically point to chair locations.
• Multiple PTZ cameras
• PTZ cameras which automatically point at sound source, or the nearest preset to the sound source.

A number of different approaches to content sharing should also be considered:

• Top end systems can have two displays (which can also be used for three-station conferences) the second display is used for content
• Lower end systems can either use PIP (picture-in-picture) or screen-splitting (if the latter 16:9 displays make sense)
• Lowest end systems switch between people and content
• Content can either be from a computer or document camera, or both; if both it must be switchable.

Finally, the type of connection must be considered, based largely on telecommunications costs, what the people you wish to connect with have, and whether you want multi-station conferences.

• While connection over the ordinary telephone network is possible, the results are not very satisfactory.
• You can connect via a non-switched serial connection but this is uncommon nowadays
• You have several ISDN connection options available, the most common being Quad-BRI (512kbps) and PRI (2Mbps but not all of this is necessarily used).
• You have a number of Internet or IP-based options, which can integrate with emerging collaboration services on the Internet.

While typically more expensive, the ISDN option has less latency (delay) related problems than the IP/Internet solutions. That is, there is less of a pause between the conversation turning round from one end to the other.

President George W. Bush, White House Chief of Staff Andy Card (left) and Admiral Richard Mies conduct a video tele-conference at Offutt Air Force Base in Nebraska, Sept. 11, 2001

Contact ECAV for an AV consultant who can help you through your choices, and provide a quotation for your tele-conferencing needs.