At the recent Voice on the Net show, AT&T said it had improved support for Avaya and Cisco IP PBXs.Before the announcement, AT&T\u2019s formal support for voice over IP was limited to VoIP-enabled routers connected to traditional PBXs. With this announcement, AT&T is certifying interoperability of Cisco and Avaya IP PBXs with the AT&T network and AT&T\u2019s VoIP services. The trials of these services are going on now, with general availability expected in the third quarter.The upshot of the announcement is that users of these IP PBXs can now connect to AT&T services without having to worry about who\u2019s responsible if the equipment doesn\u2019t function properly. It doesn\u2019t mean other manufacturers\u2019 gear won\u2019t work. Rather, these are just the first two IP PBXs to be certified.According to AT&T, the certification process is more than just testing. There are instances where the vendor's IP PBX software is actually modified to conform to industry-standard components in the AT&T network. There are technical changes made in both the IP PBX and even in our network components to better implement interoperability and new features.\u00a0This announcement raises the profile of the VoIP services within both AT&T and the traditional voice service community in general. In AT&T\u2019s case, there is no additional charge for users of its IP-based services to transport voice between sites on the AT&T portion of an enterprise\u2019s IP-based network. Rather, the VoIP traffic is simply transported as a part of the overall IP traffic. Voice traffic to specific business partners is also transported as yet another IP application.Voice calls that go off-net to the public switched telephone network (PSTN) are transported to an AT&T gateway, where they are converted into a traditional phone call. According to AT&T's VoIP product director Joe Aibinder, the pricing for this VoIP-to-PSTN traffic is not tariffed, in that there is not a regulated service price. AT&T has some standard internal pricing (list and volume discounts), but prices for large customers are typically special-bid because they may already have existing contracts and\/or other extenuating circumstances. Users can expect the price to be somewhat lower than traditional PSTN-only connections, but there will not be a drastic difference.In reality we didn\u2019t expect a great difference in price. After all, since voice services are already almost free, anything short of \u201cfree\u201d would be a relatively minor change.Next time we\u2019ll share our views on the impact of this announcement.