Re(2): Cu-SeeMe on Apple Talk

Gavin Eadie (Gavin@umich.edu)
Tue, 9 Aug 1994 23:54:19 -0400


"AppleTalk" has whatever speed it can attain on the physical medium it is
running over -- LocalTalk (the original twisted pair medium) has a 230kbps
instantanious data rate, effectively reduced by quite a lot by the collision
avoidance scheme used; EtherTalk uses 10Mbps technology, limited by its
collision avoidance and FDDITalk uses 100+Mbps rates ...

------ From: jc46@cornell.edu, Tue, Aug 9, 1994 ------

At 9:09 PM 8/9/94 -0400, David Watson wrote:
>While we have access to the "superhighway" the local feed to various
>offices on campus is via Apple talk. Is Apple talk able to carry A&V at a
>speed suitable to CuSeeMe? I ask as my attempts so far have been met with
>poor reception, broken speech, and frame speeds maxing at 0.6 fps..
>Comments and suggestions.

That's something I haven't looked at but I will, now that you've raised the
question.

What's AppleTalk's capacity? Of the top of my head, around 250kbps, isn't it?
So, on a one-to-one, with say video cap of 30kpbs, two-way, and minimum
audio of Intel DVI at 32kpbs (with push to talk rather than on all the
time), what does that give: 30+30=60, + audio 32 = 90+ kbps.

What else is chattering away on the AppleTalk?

Have you done a test late in the day, with no LaserWriters etc?
Have you tried just video only with a _low_ CAP, and no audio at all?

I'm going to have a look at this one too...

Best of luck...
Geoff R.