The H323Plus project, formerly OpenH323, has as goal developing a full featured, open source ( MPL) implementation of the H.323

Voice over IP Voice over Internet Protocol (VoIP), also known as IP telephony, is a set of technologies used primarily for voice communication sessions over Internet Protocol (IP) networks, such as the Internet. VoIP enables voice calls to be transmitted as ...

protocol. The code is written in

C++ C++ (, pronounced "C plus plus" and sometimes abbreviated as CPP or CXX) is a high-level, general-purpose programming language created by Danish computer scientist Bjarne Stroustrup. First released in 1985 as an extension of the C programmin ...

and, through the development effort of numerous people around the world, fully supports the H.323 protocol. The software has been integrated into a number of open source and commercial software products.

Software published under the OpenH323 project includes

The implementation of VoIP protocols

* PTLib - a multi-platform C++ class library. Programs based on PTLib can run on both Microsoft Windows and Unix/Linux. The library contains both the “basic” classes (strings, arrays, lists) and the higher-level functionality (networking, multi-threading). * H323Plus – a library for the development of H.323 applications. It uses PTLib for platform independence. The library has its own

ASN.1 Abstract Syntax Notation One (ASN.1) is a standard interface description language (IDL) for defining data structures that can be serialized and deserialized in a cross-platform way. It is broadly used in telecommunications and computer networ ...

parser that generates the classes for encoding and decoding of the protocol messages used in H.323.

Sample network phones implementations

* OhPhone: Command-line phone * OpenPhone: GUI for OpenH323

H.323 Related

* OpenMCU: Conference server * OpenAM: Answering machine * OpenIVR: Interactive Voice Response *

GNU Gatekeeper GNU Gatekeeper (abbreviated as GnuGk) is a free software project that implements an H.323 Gatekeeper based on the OpenH323 or H323Plus stack. A gatekeeper provides address translation, admissions control, call routing, authorization and accounti ...

H.323 Gatekeeper An H.323 Gatekeeper serves the purpose of Call Admission Control and translation services from E.164 IDs (commonly a phone number) to IP addresses in an H.323 telephony network. Gatekeepers can be combined with a gateway function to proxy H.323 ...

* PSTNGw: Serves as a gateway between H.323 and

PSTN The public switched telephone network (PSTN) is the aggregate of the world's telephone networks that are operated by national, regional, or local telephony operators. It provides infrastructure and services for public telephony. The PSTN consists ...

* CallGen323: H.323 call generator

Related Projects

Open Phone Abstraction Library In the field of VoIP networking, the Open Phone Abstraction Library (OPAL) continues the open-source openh323 project to support a wide range of commonly used protocols used to send voice, video and fax data over IP networks rather than being t ...

(OPAL)

External links

H323Plus Project page

PyH323Plus Python bindings for H323Plus using Cython

VoIP software {{network-software-stub