- PCs connected via IP to the Internet
- a camera connected to the PC
- videoconferencing software running on the PC
- a data projector to project the image on the monitor onto a screen
- microphone and speaker system.
The first three features are commonly used in standard desktop-to-desktop videoconferences. These are simply adapted for use in a teaching situation by the addition of a data projector and usually a microphone and speaker system for classroom use. In addition, a webcamera is not sufficient to view an entire class, so a camcorder is usually used, connected via a videobus to the PC. Note that this requires the use of a serial port so will not work on Windows NT.
If a network port is not available within the classroom you want to use, connections have been run successfully up to 40m from an IP port. The technique used was to connect two 20m CAT5 network patch cables using a network switch. This will, however, make higher bandwidth demands than a short connection (packets of data will be lost en route and so will be re-sent, requiring more bits per second).
Verbal feedback is a problem if the microphone is turned off to prevent echo (which is necessary if it is not possible to disable the duplex). In these situations particular attention must be paid to students' requests to ask questions. Where handheld microphones have been used participants have reported feeling very self-conscious about the process of passing round the microphone. Discussions cannot be relayed using a unidirectional microphone. Pressure zone microphones (flat mikes) are far more successful. In a dedicated videoconferencing room these should be ceiling mounted. Desk-mounted microphones can pick up extraneous noises such as paper rustling if participants are not careful around the microphone.
- use omnidirectional microphones wherever possible
- keep the microphones away from participants
- before the videoconference test that all locations can be heard
The major advantage of this method of videoconferencing is its accessibility. All of the equipment used in IP-desktop videoconferences is usually already available in the department or is purchasable at a low cost. The accessibility of the equipment means that the users have flexibility, and more importantly control, over the videoconference. In addition the technology is familiar. Since it is only a simple extension of familiar desktop applications used for videoconferencing, the setting up of the equipment does not require expert technical staff. It is also reliable, since it uses technology that is in constant use. It is also compatible with the technology many people have on their desk, enabling visiting lecturers to lecture from their office.
The limitations of this technology are the low resolution and frame rate of the video and the low quality of the audio.