We currently have a digital Norstar PBX that we are outgrowing. I want to implement VoIP but my CFO isn't on board at the moment and wants me to explore other avenues. Are there other available options besides VoIP, hybrid and the traditional phone system?
You pretty much have those three options -- pure, hybrid, and PBX. Any one of these is going to have some type of gateway to the POTS network. I would suggest that you do a good ROI for each model -- that is the way to get your CFO's attention. Don't forget to include things like features and enhancements such as being able to integrate with applications that you regularly use.