I hope following code will help you:

* For Sending Fax
ChanNum=DDEInitiate("FAXMNG32","TRANSMIT")
=DDEPoke(ChanNum,"Sendfax",'recipient("027050")')
=DDEPoke(ChanNum,"Sendfax",'attach("c:\netlog.txt")')
=DDEPoke(ChanNum,"Sendfax",'resolution("HIGH")')
=DDEPoke(ChanNum,"Sendfax",'showsendscreen("0")')
=DDETerminate(ChanNum)
=DDEexecute(ChanNum,"Sendfaxui")