A service provider can indicate externally generated phone numbers (that is, numbers for outbound calls generated externally to the computer) by setting the DisplayableAddress, CalledParty, or Comment members in the LINECALLINFO structure when processing the TSPI_lineGetCallInfo function. If TAPI has not saved its own data for these members, it leaves the data set by the service provider unchanged. If TAPI does have cached data for these members, TAPI adds its text to the end of the variable portion of the LINECALLINFO structure and overwrites the size and offset the service provider has put into the fixed portion.
A service provider can also copy an outbound number into the CalledID member. Therefore, logging applications should check the CalledID member on outbound calls if the DisplayableAddress and CalledParty members are empty.