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3G-324M is the 3GPP umbrella protocol for video telephony in 3G mobile networks.

The 3G-324M protocol operates over an established circuit switched connection between two communicating peers. 3G-324M is an umbrella specification to enable conversational multimedia communication over Circuit Switched (CS) networks and has been adopted by the 3GPP. 3G-324M is based on the ITU-T H.324 specification for multimedia conferencing over Circuit switched networks.[1][2] 3G-324M is composed of the following sub-protocols:

  • ITU-T H.245 for call control
  • ITU-T H.223 for bit streams to data packets multiplexer/demultiplexer
  • ITU-T H.223 Annex A and B for error handling of low and medium BER detection, correction and concealment
  • ITU-T H.324 with Annexes A and C for operating in wireless environment

The 3G-324M specification using the Circuit switched network allows delay sensitive conversational multimedia services such as:

3G-324M is agnostic to the actual Circuit switched network that uses it. It can run as easily over UMTS as well as TD-SCDMA networks.

3G-324M operating over a circuit switched channel between two communication peers guarantees the fixed-delay quality of service for multimedia communications. Combining Circuit switched 3G-324M services with packet-based SIP services such as presence can leverage the strength of both networks to enable new types of differentiated and innovative mobile 3G services.

Scope of 3G-324M


Audio Codec

Video Codec


  1. ^ IMTC Press Coverage Archived 2017-03-31 at the Wayback Machine, International Multimedia Telecommunications Consortium (IMTC), April 1, 2001 to November 16, 2004.
  2. ^ Orr, Eli. News & Analysis: Understanding The 3G-324M Spec, EETimes.com website. January 21, 2003.

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