I have to throw in my 2 cents worth, i used to use call wave, worked like a charm for sometime, then something changed somewhere and i could no longer received faxes, my clients kept getting busy signals, i fired Call Wave and went t\with Metro Fax Services, the price was great, there was no additional software needed, and its unlimited incoming faxes.  They cost a little bit more then Callwave but for the service i now get its worth the extra