ictfax - ICTFAX is web based and open source Fax software, It is multi users and suitable to offer online Fax services, including Email to Fax, Fax to Email and Web to Fax. ICTFAX application support FoIP, T38 and G.711 pass through faxing also PSTN fax.
RingCentral - RingCentral is the leading provider of cloud-based communications and collaboration solutions for small business and enterprise companies
ActFax - ActFax by ActFax Communication-Software GmbH - Fax Server and Email Software for Windows, Terminal Server, Citrix and Unix - ActiveFax Server
Dialpad - Switch is a cloud-based phone system built for Google Apps users.
HylaFAX+ - HylaFAX+ is an enterprise-class open-source system for sending and receiving facsimiles as well as...
Aircall - Aircall is a call center software of a new generation designed for fast growing companies. Setup instantly and integrates to your CRMs