Dual-Core SoC Simplifies VoIP Terminals and Gateways

By Veronica Hendricks
iApplianceWeb
(06/18/01, 09:55:02 AM EDT)

STMicroelectronics' new digital system-on-chip device for Voice-over-Internet Protocol (VoIP) telephony simplifies the design of enterprise IP phones, small gateways, integrated access devices, and other emergent products using VoIP technology. Called STLC1502 or “Stradivarius,” the new chip integrates a D950 Digital Signal Processor (DSP) core, an industry standard ARM7TDMI 32-bit RISC microcontroller core, two 10/100 Base-T Ethernet ports, and on-chip memory.

Voice-over-IP technology uses the same digital network used for the Internet to send and receive voice signals for telephony. Compared to the traditional approach using analog telephone lines, the Voice-over-IP approach allows voice and data services to be integrated, leading to a more efficient utilization of line capacity.

The STLC1502 integrates the various functions required to put voice over the Ethernet, resulting in a simple, more compact, and low-cost package for VoIP appliances. To design an IP phone, the only other parts required will be an analog interface, some optional flash memory for upgradeable software, and Fast Ethernet physical layer devices.

Small gateways can also be easily implemented with the Stradivarius chip by adding a multichannel telephony CODEC and subscriber line interfaces (SLICs). ST offers a broad selection of CODEC and SLIC chips.

The Stradivarius chip includes the D950 DSP, which implements the vocoder functions using ST-developed software, as well as the ARM7 microcontroller core, which performs network functions. User interface software can be easily customized. The STLC1502 is fully compliant with the ITU H.323 standard for multimedia communications over IP networks.