Address Identifiers
After address assignment, TAPI assigns address identifiers to the addresses. An address identifier is a number between 0 and the number of addresses on the line minus one. An address identifier is a permanent number assigned to a given device and remains constant even across operating system upgrades. The combination of device identifier and address identifier uniquely identifies a given address.
TAPI 2.x: Applications obtain an address identifier (and device identifier) during a call to lineMakeCall or lineGetCallInfo, in the LINECALLINFO structure, or in a call to lineGetAddressID.
TAPI 3.x: The ITAddressCapabilities::get_AddressCapability called AddressCap set to the AC_ADDRESSID member of ADDRESS_CAPABILITY will return with the plCapability parameter set to the current address ID.