OpalVOIP is a free communication software that enables you to enjoy Voice over Internet Protocol (VoIP) with ease. A fork of the OpenH323 project, this internet phone tool is an open-source program that supports a wide range of commonly-used protocols for sending voice and video data over IP networks. 

Similar to H323Plus, OpalVOIP supports the H.323 protocol but it offers more choices, as opposed to the original project’s features. This handy program is written in C++ and released under the Mozilla Public License. It also comes with the PTLib portable library for multi-platform support.

Continuing the legacy

First released in 1998, OpenH323 was developed for a full-featured open-source implementation of the H.323 Voice over IP protocol—which is one of the recommended standard protocols when it comes to reliable telecommunications. It addresses call signaling and control, multimedia transport and control, and bandwidth control for point-to-point and multi-point conferences, and is suited for transmitting calls across networks using a mixture of other protocols.

However, this project eventually stopped its development and so derivatives of the code were created instead—and one of these is OpalVOIP. Better known as OPAL or Open Phone Abstraction Library, this tool is a C++ multi-platform and multi-protocol library for fax, video, and voice communication over the internet and other networks. Aside from the H.323 protocol, it also supports Session Initiation Protocol (SIP) and Asterisk IAX2. 

In order to run on a variety of platforms, this software uses the Portable Tool Library (PTLib), which is an abstraction library. This is conveniently packaged along with the main software so there’s no need to worry about separate updates. Using this internet tool can be pretty tricky, however, as it requires knowledge of C++ and VoIP. It has enough online documentation available but it can still overwhelm beginners.

One of two choices

All in all, OpalVOIP is a great successor to the OpenH323 project. While operating the program itself can be difficult if you don’t have prior knowledge of VoIP, there are various tutorials and reading materials online that you can check out. This is the recommended software to use if you’re more interested in using other protocols rather than expanding your H.323 support, like with H323Plus.