Like any company, a telecommunications carrier is in the business of making money. Given that the market for providing PSTN connections is highly competitive, carriers typically provide a wide range of different services to better meet the need of their customers, and in turn, generate higher revenues. While the types of services offered by carriers vary widely according to market conditions, some of the elements listed below are common value-added services typically offered by PSTN providers.
Centrex. While a PBX is located at the customer premises, Centrex service offers similar capabilities and features, but it maintained and managed by the telecommunications carrier at their locations. Centrex is a great solution for companies that do not want to make the investment associated with acquiring and then managing a corporate voice network. However, Centrex typically results additional fees when services need to be added or changed.
Virtual private voice networks. While companies might choose to interconnect geographically distant PBXs using dedicated tie trunk links, this can be an expensive option, especially if multiple locations need to be interconnected. As an alternative, many service providers offer the ability to interconnect PBXs over the infrastructure of the PSTN, creating a type of virtual private voice network. This option is typically less expensive that implementing dedicated tie trunks.
Voice applications. Many telecommunications carriers offer a variety of programmed voice systems to meet the needs of different customers. For example, a company running a call center might purchase automatic call distribution (ACD) software, allowing calls to be answered automatically, and then queued for an operator. Similarly, carriers may provide a customer with interactive voice response (IVR) systems, allowing callers to provide or obtain information over the phone using voice prompts or by inputting codes as required. IVR systems are commonly implemented by government agencies to gather or distribute information from or to the public. For example, an IVR system might be implemented to allow users to pay their parking tickets by phone with a credit card.
Voice messaging. One very common additional service offered by telecommunications carriers is voice messaging. For home users, this negates the need for a separate answering machine, and for organizations eliminates the need to implement a costly voice mail server platform internally. Similar features offered by carriers include call display, distinctive ring, call forwarding, and so forth. Almost all of the services incur some additional monthly charge.
Voice or video conferencing. Another service typically offered by telecommunications carriers is voice and video conferencing services. While basic three-way voice conferencing is available for a fee on most residential phone lines, corporations often need the ability to support much larger conferences with clients, along with video capabilities as well. Costs associated with these services vary greater according to the specific requirements of the conference (voice only, both voice and video, etc), as well as the geographic distance between participants.