IChat video/audio fails to work

Question

iChat video/audio fails to work 90% of the time. The error message says the other party failed to respond, or some other, similar, bogus "communication error" message.
Invitation to video or audio chat fails 100% of the time with certain buddies of mine, and anywhere from 50% to 90% of the time with others, regardless of whether they invite me or I invite them. Changing ISPs, Macs, locations, or static/dynamic IP settings has made no difference.
This problem surfaced with Tiger in the summer of 2007, and progressively became worse, especially since Leopard, to the point where iChat video/audio fails 100% of the time, unless the other user happens to be in the same [home] network.
All of a sudden the problem went away since the upgrade to 10.5.6, and I was able to again use iChat video to communicate with friends I have not been able to "see" in a year and a half! However, the problem started again today, with the same bogus "communication error" message every time a video connection attempt is made.
Screen Sharing also fails to work, 100% of the time, regardless of how it is invoked, through iChat or not, unless, again, it is attempted between 2 macs in the same home network.
In the meantime, Skype video works fine all the time.

Answer 1

Hi,
Thomson-Alcatel by default do what is called Binding of SIP to port 5060
This means ANY SIP data is forced to that port. iChat 4 no longer uses this port for SIP. It caused problems in iChat 2 and 3 which could be resolved when the firmware was Version 4 or earlier.
How do I know ?
Personal Experience from a Speedtouch 510v4 (running version 4.2.5 firmware)
Hence the web page I linked you to.
Built up from comments on the iChat 3 forum and the iChat 2 forum since 2004
Search Results for iChat 3 (it will only go back to about Nov 14th 2005 when the software Apple Uses to run the forums changed - some active threads did cross over this date so occasional ones are older)
Smaller results from iChat 2
The work by iBoise in this forum and the ADSLGuide's Apple Forum
Known issues for the BT HOME HUB in Britain as it is a Thomson-Alcatel inside.
Because the fix on Page 4a in the orignal link I gave, worked until Version 5 firmware came out.
As I clearly said the results can be intermittent.
With non Speedtouches it tends to be a 10:10:30 split out of 50 Buddies
10 you can get all the time.
10 now and then Buddies and
30 Never successful.
The Original Version 4 Telnet command would make this 100% successful to non Speedtouch devices
In Version 5 it becomes about 15:10:25 which only marginally better.
Later versions of the firmware do not even seem to reach these figures.
Speedtouch to Speedtouch connections are better but still not 100%
I would guess you live some where where Speedtouch's are popular and have many Speedtouch to Speedtouch connections that fair slightly better than average.
Last time I had contact with iBoise on this the Firmware was at version 7 and he was in the process of evaluating it for any changes.
There has been no announcement. In this case I don't think No News is Good News.
I hope this helps.
10:42 PM Wednesday; January 21, 2009