The "cfos DSL" driver sets up an emulated modem on a virtual COM port (which is COM4 by default).
The USB data cable driver for Nokia 3510 does THE SAME on the same port (COM4)!
As long as both drivers access the same COM port, one of them is bound to fail, even while the other one might not be active momentarily.
the solution:In order to avoid conflicts, set the Nokia cable driver to COM2 before starting any phone manager. I found no such option for the cfos driver, so the Nokia driver has to move. After starting your phone manager, configure the USB cable emulation on COM2 for your mobile phone connection.
Should by any chance the cfos driver get disturbed along the way (because COM4 was occupied for a short period of time), the virtual cfos modem will disappear from the device manager (i.e. uninstall itself) and not reappear by itself once COM4 is available again. Since you need this virtual modem for your DSL connection, you will be offline!
To remedy this, simply re-install the cfos driver (without any uninstall in advance), and the virtual modem will be set up again.
© 2006 Uwe R. Hoeppe