Downloading Zoiper Softphone 5.5.10 for Mac from the developer's website was possible when we last checked. We cannot confirm if there is a free download of this app available. The application belongs to Communication Tools. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. This free software for Mac OS X was originally created by Zoiper.com.
From the developer:
This program is a converged Internet communication tool combining high-quality voice and video calls, fax, instant messaging and presence through a contact-centric intuitive interface.
You may want to check out more Mac applications, such as Allvoi Softphone, Zoiper Click2Dial or MWEB Talk Softphone, which might be related to Zoiper Softphone.