On Mon, 2011-09-12 at 14:32 +0430, hadi motamedi wrote: > Thank you very much for your help. I got the point. So it is fax over > ip provider-specific but not centos-specific. Sorry for my mistake . I > thought that it is like sip phone client issue as I didn't find > anything specific from 'yum search fax' . I discovered a few days ago Elastix which is similar to Trixbox. One of the modules is fax to PDF. A free version is available. It is based on Centos 5.6. http://www.elastix.org/ Paul.