Although the days of the PSTN are undeniably numbered, it will coexist with emerging data-centric networks for at least the next decade as networks transition to purely packetized multiservice networks. In addition, traditional service providers are already responding to the threats posed by packetized alternatives by lowering the cost of circuit-switched voice, thereby minimizing the economic incentive for customers to migrate to packetized networks. Competitive pressures due to market dynamics and entries of new players in both the local and long-distance markets are changing the perspective of incumbent carriers, and they are becoming more receptive to offering voice-over-x services. It has also been noted that the deployment models for IP and ATM access both involve the use of gateways between packet networks and the PSTN. This suggests that the PSTN will in fact be carrying traffic from packetized networks and will therefore generate revenue. In short, widespread deployment of the pure end-to-end model of packetized voice for businesses that would quickly eliminate carrier circuit-switched revenues will not emerge for several years.