Netopia 4753 2a4na Benutzerhandbuch

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Introduction   1-1
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The Netopia 4753 Voice/Data Integrated Access Devices (IADs) make it possible for small businesses to take 
advantage of the advanced communications technologies previously limited to larger organizations. By 
integrating multiple voice connections and high-speed Internet access on one DSL line, businesses can 
squeeze the most out of their communications budget.
The Netopia 4753 G.SHDSL Integrated Access Device combines a complete telephone system with a 
business-class data router to deliver a customized package of business communications ser vices over DSL. 
The Netopia 4753 suppor ts the broad array of phone features offered through your ser vice provider and uses 
your existing analog telephone equipment. The Netopia 4753 includes Netopia's sophisticated data routing 
engine 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:
 
 
 
 
  
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Office telephone systems are commonly one of two types, PBX (Private Branch Exchange) or Centrex (Central 
Office Exchange). Technically, Centrex is a subset of PBX. 
PBX users share a cer tain number of outside lines for making telephone calls external to the PBX. Most 
medium-sized and larger companies use a PBX because it's much less expensive than connecting an external 
telephone line to ever y telephone in the organization. In addition, it's easier to call someone within a PBX 
because 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 office 
instead of at the company's premises. Typically, the telephone company owns and manages all the 
communications equipment necessar y to implement the PBX and then sells various ser vices to the company.
Small- to medium-sized businesses need two kinds of ser vices: Internet presence and voice telephony. But they 
don't need the additional burden of maintaining switching equipment or administering IP and voice ser vices for 
their offices. An Integrated Access Device (IAD) that offers high-speed Symmetric (same speed upload and 
download) DSL for IP connectivity and a PBX that somebody else (the phone company) administers is the simple 
solution. 
At the phone company's central office, where all the big switch gear is, there are two kinds of switches for the 
two kinds of ser vices, voice and data. The voice switch is called a Voice Gateway and the data switch is called 
a Digital Subscriber Line Access Multiplexer (DSLAM) or access concentrator. Both the voice and data signals 
are concentrated at the DSLAM and for warded either to a data router or to the Voice Gateway. Both kinds of 
switches are manufactured by a variety of companies. The IAD must be capable of communicating with a wide 
array of possible combinations of Voice Gateways and DSLAMs.