Lets think about this logically. PHP is a wonderful language, unfortunatly its not an end all. If by fax you mean connect to a fax machine and sendout a fax (the fax machine is connected to the phoneline only). PHP cannot connect with anything that "speaks" something other than TCP/IP. Fax use PPP I believe. So to answer you question. No. If you want to connect to a fax machine, learn C/C++, JAVA (I dont even want to think about the nasty I/O stuff for this one), or something of the like (Might even be able to find a Perl module), that speaks PPP, and go buy yourself a modem!
Hope this Helps!