Further to last post, connecting with wvdial has about the same success rate for me as connecting with network-manager. The problem for me is that insertion of the modem does not reliably create /dev/ttyU0. Repeated insertions will eventually trigger /dev/ttyU0. Using sudo modprobe usbserial vendor=0x12d1 product=0x1001 always works.
Further to last post, connecting with wvdial has about the same success rate for me as connecting with network-manager. The problem for me is that insertion of the modem does not reliably create /dev/ttyU0. Repeated insertions will eventually trigger /dev/ttyU0. Using sudo modprobe usbserial vendor=0x12d1 product=0x1001 always works.