Buy a hybrid PBX integration system Hybrid IP/PBX systems allow you to reuse existing phones and also support remote phones while integrating PDA and wireless devices with your phone system. In addition, older, more traditional vendors are better equipped to support these systems. However, with hobrid PBX systems, you're dealing with a mix of new and old technologies which require a conversion between TDM and VOIP and which limits the projected lifespan of the system.

I recommend:  Polycom's exclusive LinkPlus technology provides digital interfaces to legacy PBX platforms by emulating proprietary digital telephone sets. Their system supports and integrates more than 14 different system types across the industry, like Analog and Avaya. Convergence Systems carries the Mitel 3300 hybrid PBX system.

Get a proprietary IP PBX integration system An IP PBX system will be easy to expand later. They are also easy to maintain. They are flexible and link with computer applications. They are more of a hedge against future incompatibility and they are proven, having been widely employed since 1999. On the downside, IP PBX systems are not as well understood as older systems and they are typically more expensive. Moreover, they're proprietary with fewer vendors supporting them and they might not migrate to SIP PBX integration later. That could be a concern because SIP is the emerging technology for PBX integration.

I recommend:  Cisco sells the Cisco Unified Communications Mgr, which lets you personalize your ring tone and pick up your calls from across the office. 3COM has the full-featured NBX V3000 system, with a PBX integration list that includes everything from voice mail and auto-attendant to ACD and CTI.

Maximize system synergy with a SIP PBX integration system SIP PBX systems are a great way to go because it's not proprietary and they provide you more choices of phones. They're also designed to utilize inexpensive Microsoft software. Realize though that the technology is still evolving with fewer resellers marketing SIP PBX integration than other technologies. It's still in a process of 'catching up' on features.

I recommend:  Fonality has the PBXtra system, which gives unlimited users and extensions and provides an affordable system even for small businesses. Allworx carries the Vertical SBX IP320 system with a long list of useful features.