Video Conferencing has come to the forefront within the LTER community recently. For this the digital interface standard/protocol is a determining factor. And with standards there’s always some history so some introduction to video conferencing (VC)/ video teleconferencing (VTC) are helpful:
-H.323 history: http://myhome.hanafos.com/~soonjp/vchx.html
-Instant messaging Session Initiation Protocol (SIP ) history:
http://www.showkit.com/download/samples/with/internet/html/slide6.html
-iChat: http://en.wikipedia.org/wiki/Ichat
-OV: http://www.terena.nl/publications/files/videoconf-reccomendations-dec2005.pdf
-glossary: http://www.terena.nl/activities/iptel/chapters/Glossary.pdf

I am using two instant interface environments with different standards/protocols (see I)SIP and II)H.323 below); the first I have been using for some time and the second we tested out yesterday for the first time. With two platform configurations (Karen/Shaun: $130 isight camera; free xMeeting on mac; Don: $50 logitech camera; $105 Polycom PVX8.0 on pc) we made successful xmeeting tests with mac-mac (Shaun/Karen; Shaun/Mick) and with mac-pc (LNO set-up; Don interactive).

The lessons learned for H.323 include:
-must turn off firewall or caller receives msg “far site could not be reached”
-set microphone to external (ie isight) microphone (instead of built-in)
-use headphones to remove feedback
-desktop sharing is poor resolution; requires further investigation

I) Aim: a stand-alone proprietary AIM (AOL Instant Messanger) client software available for free for MSWindows, Mac OS, Linux, Wiondows CE and Palm OS.
protocol: Standard SIP protocol
Mac Side: iChat AV shipped with platforms; four-way multi conferencing available in recent system software though must be initiated with G5 architecture
http://docs.info.apple.com/article.html?artnum=301050

II) Polycom VC: standalone hardware units or client software for purchase
protocol: H.323 standard set by the International Telecommunication Union (ITU)
ITU H.323 compatible VC clients
Polycom hardware for small/medium multiple conference groups:
Polycom VSX5000 (~$3500); VSX7000x (~$5500); V500 (~$150)
PC Side standalone config: : PVX software with a Logitech camera ($160)
as alternative to V500 or VSX300
Mac Side: ohphone or xmeeting as next generation (open source)
xmeeting 0.2 is at xmeeting.sourceforge.net; recommended for tiger;
has all ohphone features; built on new architecture
in xmeeting preferences need to h.323/enable h.323; SIP enable SIP