Most telephony features are provided by the telecommunications switch or the telephony network. Examples are call waiting and calling number identification. Literally hundreds of features and combinations of features are available. Some telecommunications systems allow the service provider to create new features as subscribers request them from the service provider. Your ability to offer these features and create new ones is part of the design of your equipment.
Different architectures provide different degrees of flexibility.
Both initial costs and upgrades can vary substantially across vendors. As I discussed in my April column, IP telephony adds even more complications to how subscriber features can be offered. A consultant can help you to recognize the key differences and evaluate their impact on your ability to evolve with your market. A telephony consultant can help you sort out the alternatives and interfaces for call accounting. The accounting for telephony charges is built into a telephony switch.