From Serebra Learning Corporation
VoIP Services 
This module introduces
VoIP Services. We define and explain packet telephony, its benefits and potential pitfalls, and why private users, small and large businesses, and the industry press see this technology as the next great telecommunications revolution. We introduce the many components that make up a converged voice network, and examine their roles. We explore the market drivers pushing
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Digital Subscriber Line 
To explain the various technologies used to provide digital subscriber lines
Network managers, builders of wide area networks, systems engineers, and technical support staff
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