User`s guide

5 Discussion
5.1 Videoconferencing Reciprocity Application
The videoconferencing reciprocity applications were the first part of the system to be developed. As
mentioned in Section 4.1, the software was developed in Visual Studio only after it was discovered
that Cygnus did not support serial port communications. Having no previous experience developing
under Visual Studio, much of the first few months of development was spent learning how to use
Visual Studio, MFC, the Winsock API and Windows resources.
As mentioned in Section 4.1, the current release version of the VAN II software, version 2.0, runs
under OS/2. First Virtual’s next version, 3.0, which is still in beta, runs under Windows NT. The
VAN II software for Windows NT was first requested in March 2000, but was only sent, after many
requests, in September. However, the package was incorrectly addressed, and took a number of
weeks to arrive. VidServer and VidClient were developed independently of any VAN software.
The VAN II software received was version 3.0 beta 2, released in June 2000. Documentation for
the software was available from First Virtual’s web site. This included a manual for version 2.0, and
an addendum of changes since version 2.0.
The existing VAN II 2.0 software is controlled using Audio Visual Services (AVS) command-line
scripts. AVS is the software that controls the audio-visual functionality of the VAN. This software
is also referred to as MOS H.310. In VAN II 3.0, the AVS commands are not available directly.
A configuration program called “VAN Resource Manager” replaces the command-line scripts, and
currently there is no way to replace command-line scripts for action such as “start AVS” and “stop
AVS”. However, further examination of the features of VAN II 3.0, or an update in a future version,
may solve this problem. As previously mentioned, the author is not involved in upgrading the VANs.
In addition, the original VAN 2.0 software is being used while the software is upgraded on separate
hard disk drives. The VAN computers have currently not been completely set up to run the VAN
3.0 beta software, which is unfortunately beyond the author’s control. Since the new software has
not been installed the application could not be tested in situ.
Despite this, all components of VidServer and VidClient have been tested — reading from and
writing to the serial port, sending data to the server or clients, receiving data from the server or
clients, and executing script files all work. When the VAN it set up with the new software, any
changes to the application will be minimal, if any are required at all. Most settings can be changed
by editing the preference files as described in Section 4.3.
As mentioned in Section 4.3, a test mode has been implemented in VidClient (VidServer does not
require a test mode), which has been used to test all aspects of VidServer and VidClient except for
serial port communication. Serial port communication has been tested separately.
VidClient and VidServer have been left running in test mode for approximately eight hours con-
tinuously. This is important, because it is likely that, in practice, these applications will be left
running continuously for many days. In normal use, the infra-red motion detector is likely to send
an “on” or “off” message about once every minute. Since VidClient’s test mode sends messages to
VidServer every five seconds, eight hours of test mode represents many days of actual use.
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