I have taken BSNL Broadband connection on 16Apr2009 and I too was given Siemens C2110 Modem. When I tried to install the USB driver, I too faced the same problem. When I called BSNL customer care (through 1500 / 18004241600), their service person came and informed that usb driver is not getting installed due to faulty
windows OS and set the connection through LAN port (ethernet port).
Last weekend, I tried to explore why usb driver is not working. I created an empty partition and loaded Windows OS (Windows XP SP3) afresh. After loading Windows, before loading any other drivers, I connected the Siemens C2110 modem through USB port and I could set up the driver automatically without any error.
Then, when I tried to load other drivers, I found that the driver for internal (dial-up) modem is not getting loaded and continue to remain as unknown device
Thus, I have found that there is conflict between drivers of internal modem and USB driver for Siemens C2110 modem and have come to conclusion that if anyone want to use this Siemens C2110 modem through USB port, one must uninstall and disable the internal modem first.
Hey I am also using
Nokia Siemens C2110 via the USB port. The driver did not get installed with the automatic set up with the CD. The only way to install this USB driver is to let Windows automatically detect the modem and then set the path for the CD. But no conflict for me as such !