4.8. Issuing a Send Fax Function

• 4.8.1. Send Fax Issued by the Transmitter
• 4.8.2. Send Fax Issued by the Called Application
• 4.8.3. Status of Fax Transmission

After defining fax data in one or more DF_IOTT structures and following other recommended steps as outlined in Section 4.2. Guidelines for Implementing Fax (page 42), you can issue the fx_sendfax( ) function in your application.

The fx_sendfax( ) function transmits fax data as specified by a table of DF_IOTT entries. This function can be issued by the caller application or the called application. The called application issues fx_sendfax( ) in a polling fax transmission or to block incoming faxes. See Section 3.4. Types of Fax Transmission on page 29 for more information on the types of fax transmission and application flow.

When the initial fax connection is made, the caller station is initially set as the fax transmitter and the called station as the fax receiver.

4.8.1. Send Fax Issued by the Transmitter

The transmitter (which can be the caller or the called application depending on the type of fax transmission) issues fx_sendfax( ) to send fax data to the receiver as specified by DF_IOTT entries. Any receiver incompatibility disconnects the call and ATDV_LASTERR( ) returns an error code of EFX_DISCONNECT.

In synchronous mode, the function returns a -1 to indicate that an error has occurred. In asynchronous mode, a TFX_FAXERROR event is generated.

In a turnaround polling fax transmission, set the io_phdcont field to DFC_EOM for the last DF_IOTT entry before issuing the initial fx_sendfax( ) function. For more information, see Sections 3.4.3. Turnaround Polling Fax Transmission (page 34) and 4.5.9. Setting Phase D Continuation Values (page 53).

4.8.2. Send Fax Issued by the Called Application

A called application issues an initial fx_sendfax( ) function to the caller application to indicate that the called application is only capable of transmitting a fax.

• If the caller is capable of receiving or wishes to receive a fax transmission, the caller issues an fx_rcvfax( ) or fx_rcvfax2( ) function to receive the fax data.
• If the caller is not capable of receiving or does not wish to receive a fax transmission, the called application disconnects the fax call.

The called application can also issue fx_sendfax( ) in a polling fax transmission. For more information, see Sections 3.4.2. Polling Fax Transmission (page 30) and 3.4.3. Turnaround Polling Fax Transmission (page 34).

4.8.3. Status of Fax Transmission

Status information on the fax transmission is available using the fax extended attribute functions.

• During fax transmission, the state of the channel device is set to CS_SENDFAX. To obtain the current state of the channel device, issue ATFX_STATE( ).
• If the function successfully completes, the final Phase D status is available using ATFX_PHDCMD( ) and ATFX_PHDRPY( ). For more information on Phase D status values, see Appendix B.
• To obtain a pointer to the last DF_IOTT entry that was processed, issue ATFX_LASTIOTT( ).

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