# Transmit and receive documents functions

The following functions control fax operations:

Function | Synchronous/ Asynchronous | Description
--- | --- | ---
nfxSendFax | Asynchronous | Starts negotiating with the remote fax receiver and subsequently sends all the documents in the send queue.
nfxReceiveFax | Asynchronous | Starts negotiating as the called fax terminal and then places all received documents into the receive queue.
nfxAnswerFaxPoll | Asynchronous | Provides a queue of documents to send in response to a poll request from the remote sending fax terminal.
nfxStopSession | Asynchronous | Stops a fax send or receive operation in progress.