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This paper presents a system on chip (SOC) based high-density carrier class Voice over Internet Protocol (VoIP) media gateway. The design exploits three levels of parallelism namely HW/SWpartitioning, multiprocessing and instruction level parallelism. The system facilities the carrier class service providers to transform channels on PSTN network to IP network, enabling the consumers to enjoy several value added services, such as voice, data, fax and video all through a uniform network at lower cost. The SoC implements a high-density media gateway switch for carrier class VoIP applications. The solution is synthesized to operate at 266 MHz handling up to OC-3 data rate port density equivalent to 2016 simultaneous calls on a single chip and it can be cascaded to support OC-12 and OC-48 rate port density on single board in different configurations. On each channel the SoC supports up to 128 ms tail length G.168 compliant Line Echo Cancellation (LEC), voice activity detection (VAD), comfort noise generation (CNG) and discontinuous transmission (DTX), dual tone multi frequency (DTMF) detection and generation, variety of G.xxx voice codecs, V. 17 Fax and V.34 data modem standards and MPEG4 video compression/decompression algorithms. The solution is compared with the existing architectures and commercial products; it offers 3x to 10x cost, size, power and port density performance improvements with IP and PSTN internetworking support. The media gateway system based on the presented architecture has been used to develop IP-based automatic call distribution (ACD) by etel Pvt. Ltd and installed in Telephone Inquiry Exchange of Pakistan Telecom and its variants are being tested by Buraq Telecom for installation in their service network.