For ActiveFax installed on the same server as Unity the default file extensions for attatchements in an email that are supported for rendering are limited to .TXT, .BMP, and .TIF. The reason for this is rendering document types like .DOC, .XLS etc... are very expensive on the CPU and in most cases require that you have an application installed on the server that can print those types of documents (i.e. you'd need to install Office on the Unity server as well).
Most fax packages, LightningFax included, will simply request of the OS to print the attached document to a special printer driver installed on the server that dumps it's output to a TIF file instead of a printer. Print jobs, as I'm sure folks know, are a CPU hog and will chew up all the CPU for a period of time on the box itself. This interferes with real time call processing capability so we yanked support for it on the local server. .TXT and .BMP files can be rendered on the fax cards themselves (i.e. GammaFax supports on the fly rendering of .TXT files using on card resources).
If you want to install the fax server off box, you can loosen the limitation up all you want. It can be configured to attempt to fax any type of attached document that the fax server has applications to handle. This is one of the many reasons we will no longer be supporting on box fax services in 3.0 moving forward... for anything more than the smallest deployments and in limited usage scenarios, it's not practical.
Jeff Lindborg
Unity Product Architect/Answer Monkey
Cisco Systems
lindborg@cisco.com
http://www.AnswerMonkey.net (new page for Unity support tools and scripts)
