Telephone, data and videoconferencing over the Internet
There is an on-going debate around the advantages of e-mail over telephone calls, but clearly each has its role to play in a business communications strategy. One of the advantages of the telephone is the ability to get an instant response - it is a synchronous form of communication - and to gauge the reactions of the person you are communicating with through the inflections in their voice. E-mail attempts to reproduce this have been made with the development of emoticons, those symbols often found in e-mail messages which some people can find rather irritating.
The Internet offers several forms of synchronous communication, including voice telephony, data and video conferencing. In each case, the effectiveness of the communication, measured by the quality of the signal and its closeness to real time, is dependent on the amount of bandwidth that is dedicated to the application. Any delays in the transmission of the audio or video components will distort the sound or picture, and may even make them unintelligible.
Voice telephony (VoIP)
Making standard telephone calls over the Internet, or Voice over IP (VoIP), is in theory a perfectly viable option, with the analogue signals carried as digital data packets over a combined voice and data network, however current bandwidth limitations mean it is still unreliable. BT and other Internet Access or Virtual Private Network providers offer VoIP functionality between their own subscribers, but in these cases the call is not transferred over the open Internet, but is routed over dedicated bandwidth on the provider's own managed network.
Data conferencing and application sharing
Dataconferencing, where typed messages are transferred over the Internet in (near to) real time and all parties conference simultaneously, requires significantly less bandwidth and hence is more practical. Popular applications on the Internet include Internet Relay Chat (IRC) and chat rooms. For business users, application sharing, where several parties can work on the same document or other application at the same time over the Internet, is feasible using a standard telephone line and a modem. A point-to-point conference, using dedicated bandwidth and a minimum of two channel ISDN is better. NetMeeting, a free software application from Microsoft used over the Internet, is worth experimenting with for application sharing.
Videoconferencing offers the facilities of a telephone or conference call with the added benefit of seeing the caller, which can offer significant advantages as well as reduce your travel costs. Virtual meetings can be set up with business partners anywhere in the world, and remote workers or salesmen can communicate face to face with their colleagues in the central office while they are working from home or travelling.
A videoconference can be set up over the Internet, a local area network (LAN) or a point-to-point ISDN link with two or six channels, but the key to a successful conference is the amount of dedicated bandwidth available. Videoconferencing over the Internet using a standard telephone line and a modem is possible, but the heavy image data demand and Internet congestion allow only postage stamp size video windows and slow frame rates, delivering a quality not generally acceptable for business purposes. Connections over the Internet should not be relied on when video or even voice is of critical importance, although the audio side of the conference suffers less, as it requires less bandwidth and usually takes precedence over video, the whole conference is still in competition with other users for bandwidth over the public Internet. A ‘broadband’ Internet connection can allow reasonable quality videoconferencing with a maximum of say 256kbps upload at each end, but local contention and public Internet congestion will quickly degrade the usability.
An ISDN connection with a minimum of two channels is the entry-level solution for a reliable videoconference, and a point-to-point connection offers better quality and functionality. The dedicated bandwidth provided guarantees that the quality of the conference will be the same from the first to the last minute, and unlike the Internet it will not be influenced by traffic load generated by other users.
Six channel ISDN is a minimum for room or team videoconferencing, and for conferences where more than two sites are participating. Eight channel systems are available, incorporating a built-in MCU (multi-point connection unit), which allows up to four parties to join the conference with two channels each. These systems are voice activated, meaning that users are able to see the person speaking at any time. MCUs can also be hired, at a cost of around GBP50 per hour per connection plus call costs.
The equipment needed for videoconferencing includes a video board PC card, a camera to capture images and videoconferencing software.
- video board card - compresses and decompresses the video signals. High specification cards compress more frames per unit of time, resulting in a better quality picture. The human eye sees a picture as perfect when the frame rate is higher than 30 frames per second, and adequate when the rate is higher than 15 frames/sec.
- camera - select carefully, in particular the provided resolution, zoom and focus. Some application-specific cameras are available, such as intra-oral cameras for dental applications and document cameras for capturing or magnifying documents or small objects.
- videoconferencing software - functionality to look out for includes the ability to control the camera on the local site or even at the remote end of the conference, and voice recognition software.
Reviewed January 2011
last updated : 21/01/2011
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