Re: audio problem - Mac

John Ingham (
Fri, 28 Feb 1997 16:51:31 +0930

Michael Kankiewicz said...

>Hello all. I just started using cu, and I'm having one big problem. I'm
>not getting any incoming audio. The person on the other end can hear me
>but I'm told the sound is quite bad. What's odd is that I get sound when
>monitoring myself or even calling my own ip address (I have an ethernet
>connect), but nothing from someone else. I realize the computer I'm using
>for this is quite slow, but shouldn't I be hearing *something*?
>System: Macintosh IIfx 68030 40 Mhz, fpu, 16RAM, b&w quickcam, ethernet.
>Any ideas? Thanks much.

Michael, I would have thought that use of a 68030 processor for
Transmitting sound is marginal at best and maybe just not quite possible.
However, you are complaining specifically about not being able to Receive
sound. Now that is possible even on my old LC-1 which uses a 68020, so I
think that your using a 68030 shouldn't be what's stopping you from hearing

I notice that your network connection is via ethernet. Many Network
Managers install a firewall to prevent hackers messing with their system,
but this firewall at the same time plays havoc with CU-SeeMe. Could it be
that not ALL the ports required for CU-SeeMe have been activated?
According to Bill Woodward, these are port numbers 7640-7648; check with
your Network Manager.

When you call your own IP address, the packets never even leave your own
machine but are simply looped back internally which could explain why that
works but nothing else. Is there anyone else on your LAN also running
CU-SeeMe with whom you could test? That at least would at check my
firewall theory.

John Ingham
Supervisor, Technical Operations, CALS (Centre for Applied Learning Systems)
Adelaide Institute of TAFE (Training and Further Education)
GPO Box 1872 Adelaide South Australia 5001
Ph: +61 8 8207 8550 Fax: +61 8 8207 8552
Web Site: