The basic function I'm trying to perform is to determine whether or not a user's Internet connection may be via a modem (or similarly slow device) or not, without going to the trouble of trying to download a file and determine transfer rate. My plan was to do so by checking the hardware speeds of any connected/active network interfaces; modems won't be higher than 115200bps, while network cards will be 10Mbps or higher. It's imperfect, given that I can't determine which interface will actually be used to access the Internet, but adequate and theoretically easy.
I had planned to use the function GetIfTable in IPHLPAPI.DLL, as that looked like it would do everything I need; however, it appears that that API doesn't consider a modem to be a network interface, and as such it doesn't return any information on modems in the system.
So, can anyone shed some light on how I might do this?