Check the Modem control panel

1. From Apple Menu Items point to Control Panels and select the Modem control panel.
2. From the drop down list select iMac internal 56k.
3. Close the Modem control panel.

   

4. Click the yes button to save changes.

Make sure AppleTalk is disabled in the AppleTalk
control panel

1. From Apple Menu Items select the Chooser icon.
2. Select AppleTalk Inactive
3. Click the OK button.
4. Close AppleTalk control panel.

   

5. From the menu bar, click Special and select Restart.