Introduction 1-1CCCChhhhaaaapppptttteeeerrrr 1111IIIInnnnttttrrrroooodddduuuuccccttttiiiioooonnnnOOOOvvvveeeerrrrvvvviiiieeeewwwwThe Netopia 4752 Voice/Data Integrated Access Devices (IADs) make it possible for small businesses to takeadvantage of the advanced communications technologies previously limited to larger organizations. Byintegrating multiple voice connections and high-speed Internet access on one DSL line, businesses cansqueeze the most out of their communications budget.The Netopia 4752 SDSL Integrated Access Device combines a complete telephone system with abusiness-class data router to deliver a customized package of business communications services over DSL.The Netopia 4752 supports the broad array of phone features offered through your service provider and usesyour existing analog telephone equipment. The Netopia 4752 includes Netopia's sophisticated data routingengine optimized for small and medium size business needs. These business-class features include IP routing,firewall, NAT, MultiNAT, DHCP and both PPTP and IPSec VPN functionality.This section covers the following topics: “Features and Capabilities” on page 1-1 “How to Use This Guide” on page 1-2FFFFeeeeaaaattttuuuurrrreeeessss aaaannnndddd CCCCaaaappppaaaabbbbiiiilllliiiittttiiiieeeessssOffice telephone systems are commonly one of two types, PBX (Private Branch Exchange) or Centrex (CentralOffice Exchange). Technically, Centrex is a subset of PBX.PBX users share a certain number of outside lines for making telephone calls external to the PBX. Mostmedium-sized and larger companies use a PBX because it's much less expensive than connecting an externaltelephone line to every telephone in the organization. In addition, it's easier to call someone within a PBXbecause the number you need to dial is typically just 3 or 4 digits.Centrex is a newer variation on the PBX. It is a PBX with all switching occurring at a local telephone officeinstead of at the company's premises. Typically, the telephone company owns and manages all thecommunications equipment necessary to implement the PBX and then sells various services to the company.Small- to medium-sized businesses need two kinds of services: Internet presence and voice telephony. But theydon't need the additional burden of maintaining switching equipment or administering IP and voice services fortheir offices. An Integrated Access Device (IAD) that offers high-speed Symmetric (same speed upload anddownload) DSL for IP connectivity and a PBX that somebody else (the phone company) administers is the simplesolution.At the phone company's central office, where all the big switch gear is, there are two kinds of switches for thetwo kinds of services, voice and data. The voice switch is called a Voice Gateway and the data switch is calleda Digital Subscriber Line Access Multiplexer (DSLAM) or access concentrator. Both the voice and data signalsare concentrated at the DSLAM and forwarded either to a data router or to the Voice Gateway. Both kinds ofswitches are manufactured by a variety of companies. The IAD must be capable of communicating with a widearray of possible combinations of Voice Gateways and DSLAMs.
