Does "trixbox CE" to free use and free of charge.

Dear all
i find the page that is about to trixbox CE.
"http://www.trixbox.com/about-us/terms-and-conditions"
but i am not a perfessional for law relation..

i only want to know . in commonly or can i use trixbox CE
for free use and free of charge..
( the "use" is mean only simple to use "Trixbox CE" to build an softphone to softphone
environment in my company , to provide company'employee free use.)

not modify and distribution and other any thing
and no-make business to other people.

can any one tell me.. or
explain to my understanding..

PS: softphone is Zoiper that is free too.