7.10 Conclusion

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Despite their humble beginnings more than 125 years ago, PBX systems still have plenty of room for innovation. Today’s PBXs emphasize integration into enterprise network infrastructures, thereby addressing the applications that are most in demand: LAN interconnectivity, wireless for increased mobility, videoconferencing, and multimedia applications. Accordingly, there are PBX add-ons that support in-building mobile communications using wireless technology, and those that can also be connected to LANs and IP networks, allowing users to send e-mail and run realtime and multimedia applications such as voice calls and videoconferences more economically.

Over the WAN, VPNs permit the creation of voice and data networks that combine the advantages of both private facilities and public services, drawing on the intelligence embedded in the carrier’s network. With services and features defined in software and implemented via out-of-band signaling methods, users have greater flexibility in configuring their networks from on-premises terminals and management systems. With a VPN, businesses can save significantly over traditional dial-1 rates on calls between on-net locations, including calls placed by mobile employees using the VPN phone card. With custom-dialing plans, corporate employees can simply dial extensions to place long-distance calls and, with accounting codes, telecom managers have an easy way to track costs and charge back users.

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