if (mail_type=="sff"): # normal fax file
                        # sff -> tif
                        ret=os.spawnlp(os.P_WAIT,"sfftobmp","sfftobmp","-tif",attachment,basename+"tif")
                        if (ret or not os.access(basename+"tif",os.F_OK)):
                                raise "conv-error","Can't convert sff to tif. sfftobmp not installed?"
                        # tif -> ps -> pdf
                        # the first pipe must be handled by the shell so that the output of
                        # of ps2pdf can be read immediately. Handling this shell in Python
                        # leads to an overflow of the ps2pdf output pipe...
                        command="tiff2ps -a "+escape(basename+"tif")+" | ps2pdf - -"
                        tiff2pdf=popen2.Popen3(command)
                        if (tiff2pdf.poll()!=-1):
                                raise "conv-error","Error while calling tiff2ps or ps2pdf. Not installed?"
                        tiff2pdf.tochild.close() # we don't need the input pipe
                        # create attachment with pdf stream
                        filepart = email.MIMEBase.MIMEBase("application","pdf",name=os.path.basename(basename)+"pdf")
                        filepart.add_header('Content-Disposition','attachment',filename=os.path.basename(basename)+"pdf")
                        filepart.set_payload(tiff2pdf.fromchild.read())
                        tiff2pdf.fromchild.close()
                        ret=tiff2pdf.wait()
                        if (ret!=0):
                                raise "conv-error","Error "+str(ret)+" occured during tiff2ps or ps2pdf"
                        os.unlink(basename+"tif")
                        email.Encoders.encode_base64(filepart)