The transition from switched to packet networks continues at a rapid rate, leaving providers clamoring for high-performance, highly functional, low-cost voice-over-IP (VoIP) solutions.Recent figures from research company Dataquest tell the story. Carrier-class VoIP gateways reached $250 million worldwide in 1999, with an expected growth rate of nearly 100% compounded annually through the year 2003.
While the market is exploding, many technical issues must be addressed, such as voice quality, quality of service (prioritization of packets), encryption, and interoperability. Additionally, the cost of implementation remains excessively high, and the time-to-market pressures are in proportion to the rate of market growth.
Within this framework, Mitel Corp. of Ontario, Canada, has introduced its IP phone chip set and software, which combine all of the hardware and software building blocks necessary to meet these demands. The chip set comprises the MT92102 phone controller, the MT92303 dual codec, and the NWK933 3.3-V PHY for 10/100Base-T Ethernet.
The MT92102 handles the protocol stack management and the DSP packet-processing algorithms. It's made up of an ARM7-Thumb CPU running at 40 MHz, a 90-MIP OAKDSPCore DSP, and a full 801.1p 10-/100-Gbit/s Ethernet bridge, while including full-duplex operation. The device also is available in a lower-performance version with a 25-MHz CPU and a 60-MIPS DSP—with half-duplex operation (see the figure). The chip provides on-chip hardware acceleration for DES or IP Sec security functions.
The MT92303 is a full-featured dual codec with drivers for hands-free, speakerphone, handset, and line operation. No external components are required. The NWK933 CMOS PHY is compatible with the auto-negotiation section of IEEE 802.3u, and it supplies all of the functionality needed for full-duplex operation.
Full-duplex operation is key here. Packet-based networks must withstand long delays without introducing echo. Some systems fall into the half-duplex mode and cannot eliminate all residual echoes. Mitel gets around this by using Trueplex technology. This algorithm tracks changes in the echo path to provide fast reconvergence for clearer voice signals.
The MT92102 comes in a 208-pin TQFP or 286-pin BGA, while the MT92303 is in a 44-pin TQFP. Pricing for both models is $17.36 each in 100,000s. The NWK933 comes in a 64-pin TQFP and costs $3.00 each in 100,000s.
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