User`s guide

Figure 12: IRClient main window
devices are not pointing directly at each other, or if the connection is temporarily broken by someone
walking in between the two devices. As also mentioned in Section 2.6, IrDA will also vary its baud
rate to maintain a “good” connection (low error rate). Bright light, for example, can introduce
errors. In any case, most files sent through infra-red are small text files — business cards, memos,
etc — perhaps 4K at the most.
As with VidServer and VidClient, the settings are stored in preference files. The “server.prf”
file just contains the TCP/IP port number on which to listen for connections. The “client.prf”
file contains the TCP/IP port number on which to contact the server (this should match the port
number in the “server.prf” file), and the COM port name and baud rate of the port to be used for
tunnelling data. Either the long or short port names can be used. Physical port names (such as
COM1 or COM2) can be substituted if a non-infra-red transceiver is to be used. If either preference
file doesn not exist, standard settings are used.
IRServer, like VidServer, does not poll its clients, so if the connection dies, both the server and
clients need to be quit and relaunched to reestablish the connection.
4.5 Camera Position
As well as the two main improvements to the videoconferencing system (the videoconferencing
reciprocity application and the infra-red tunnelling application), the camera position has been raised
to approximately 1.2 metres above the floor, and is set in the wall, with the projected light being
blocked around the camera lens.
This height is suitable for seated face-to-face conversation, and is a major improvement over the
previous height of approximately 60 cm.
The author was not involved in the repositioning of the camera, but because it was part of the
original design, it has been incorporated into the study.
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