This function maps a phone number or address assigned to a line device back to its dwAddressID. The phone number address range is from zero to the number of addresses minus one returned in the line device capabilities (lineDevCaps). Given that dwNumAddresses in lineDevCaps is 1, this function always returns 0 in the DWORD pointed to by lpdwAddressID.

LONG
WINAPI
lineGetAddressID(
HLINE hLine, 
LPDWORD lpdwAddressID, 
DWORD dwAddressMode, 
LPCSTR lpsAddress, 
DWORD dwSize 
);