We did some testing with this and believe we have discovered the problem.
This is not really a software conflict but rather a customer-usage issue.
We did a lot of testing with the GeoPort and the Extensions Manager and the
only way I could get the problem, where the "phone turned black" and the
Express Modem was unusable, was:
* To have turned off the Extension Manager's own extension, EM Extension,
when the other extensions were turned off.
* NOT to turn it back on when the other extensions were turned on.
If the Express Modem was turned off, with and without turning off its own
extensions, we could always get it turned on successfully -- as long as
the EM Extension was not turned off and left off.
The key to knowing whether the EM Extension is off, is to check where the
Extensions Manager icon loads at boot. If it shows before the other
extensions, then it is on; if instead it shows after the extensions and
before the Express Modem icon, then it is off, and the phone will go black.
Then yes, the only way to get the Express Modem back and functional is to
reinstall the GeoPort software.
So, in summary, the key is to NOT turn off the EM Extension (equals don't
turn off all extensions unless you really have to). If you do have to turn
it off, BE SURE to turn it on in the Extensions Manager Control Panel
BEFORE rebooting! Having the Extensions Manager half on/off is the actual
problem.