This has been culled from postings and edited a little by me:

>Does anybody have any suggestions or experience running CU-SeeMe
>with a Mac 7500/100 running system 7.5.2?  I am running OT 1.0.8 and
>freePPP 1.0.2.

Concerning using CU with an Apple 7500  there are two things to keep in mind.

a) CU does not work with Open Transport 1.0.8
b) CU has a problem with virtual memory on a 7500

Update:  reports are that it works fine with Open Transport 1.1b16.

There are two messages posted on this list concerning this before and
I will quote them here:

>1.  Install OpenTransport COMPLETELY.
>
>2.  Remove from the Extensions folder the libraries named "Open Tpt Internet
>    Library" and "OpenTptInternetLib".  These are the libraries that 
have the
>    code for mishandling dialup connections.  Also remove the TCP/IP control
>    panel.
>
>3.  Make sure that you have MacPPP 2.1.1SD or later (I use 2.2.0a) and 
MacTCP
>    2.0.6 or later.  Any version of FreePPP is fine.  If you don't have 
these,
>    they're available in the usual places.
>
>4.  Turn off virtual memory.
>
>This will permit AppleTalk to operate properly, but will supress OT's 
handling
>of PPP networking.
>
>Once I did all this, my 7500 was very happy to work and use built-in video
>(with 0.83b2).

This one was from Mark Hartman, and the next is from Tim Dorcey:

>Currently, CU-SeeMe (83b3) will only work on a 7500 if you turn off Virtual
>Memory, so make sure you buy lots of real memory.  We *hope* to soon 
have a
>work around that will allow digitizing with Virtual Memory on.

Even wih OT 1.1b16, turn off virtual memory.