Unified messaging isn't a new concept, but IP telephony vendors are spicing up their unified messaging offers with advanced user interfaces and more accurate voice recognition and text-to-speech technologies.

In typical installations, the unified messaging system is a software add-on to a PBX system that works with it to provide efficient, consolidated, "hands-free" access to voice mail and e-mail via any phone device, located anywhere. In most cases, the unified messaging system handles the voice mail directly from the PBX and provides the processing necessary to integrate the voice mail and e-mail via a LAN connection to the e-mail server.

In this Clear Choice Test we evaluated the latest unified messaging packages from IP telephony vendors Avaya, Cisco, Nortel and Siemens Communications . A subsequent test is planned of stand-alone and third-party unified messaging offerings.

Avaya topped the competition because of its well-done Web interface to unified e-mail and voice mail, superior voice-recognition interface, and outstanding TTS accuracy and performance.

Siemens placed second, with its major strengths being exceptional administrative access to the unified messaging environment, a very good Web interface to unified e-mail and voice mail, and tailorable voice recognition options.

Cisco boasts exceptional survivability options and added voice mail security . There were some missing pieces, though, such as no Web interface to unified voice mail and e-mail, and no voice-recognition access to e-mail.

Nortel's strengths included broad language support and tailorable voice recognition. Architecturally its unified messaging only works with Nortel PBXs. Nortel's TTS readout (what you hear as the unified messaging system is reading your e-mail to you) was poor, comparatively speaking, and a proprietary voice mail-encoding format complicates matters by requiring that a Nortel-specific player be installed on your laptop to play the message.

All packages tested comprised one or more servers, client software and the underlying telephony infrastructure to fully exercise the unified messaging features specified in our test plans (see "How we did it" ).

For consistency, we standardized on Microsoft's Exchange e-mail message store and the Outlook e-mail client. Each vendor provided an Exchange server (2000 or 2003) and any necessary Outlook client plug-ins.