Designed for wireless voice over Internet Protocol (VoIP) applications, the AT76C901 integrated circuit (IC) from Atmel Corporation (San Jose, CA) is a single chip capable of running VoIP software, firmware for IEEE 802.11b wireless local area networks (WLANs), and voice compression/decompression. The highly integrated chip consists of an ARM7TDMI RISC processor for running VoIP protocol stacks and two subsystems: one has an ARM7 processor and 802.11b media access controller (MAC) and the other has an OakDSPCore digital-signal-processing (DSP) core and integrated voice codec. The OakDSPCore performs voice compression and decompression according to International Telecommunications Union (ITU) standards such as G.711, G.732.1, and G.729ab. The integrated chip requires only SDRAM, flash memory, liquid-crystal display (LCD), keypad, battery, 802.11b baseband processor, and RF front end to create an entire wireless VoIP telephone handset.
According to George Zapantes, VoIP Project Leader for Atmel's Multimedia and Communications Product Group, "with the WLAN market growing as quickly as it is, this device as a wireless VoIP phone allows business enterprises the ability to leverage their WLAN infrastructures in order to lower their long-distance phone charges. Additionally, as the number of hotspots continues to grow, VoIP phone services could also become available at these sites." The company offers a complete reference design kit (the model AT76C901-DK) based on the model RF3000 baseband processor, RF2958 single-chip transceiver, and RF5117 power amplifier from RF Micro Devices (Greensboro, NC). The kit includes complete schematic diagrams, Gerber layout files, bill of materials, and software.
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