Web VoIP Directory

Times were there when a long distance, especially international call cost to 10 USD per minute. The advent of Voice of Internet Protocol (VoIP) has reduced the same to a lower than US $ 0.1 per minute. The individuals as well as businesses have migrated to VoIP to reduce their communication costs, which has threatened and almost diminished future of legacy Public Switched Telephone Network (PSTN). For individuals, thousands of Long Distance and International (LDI) call service providers, prepaid card companies and internet telephony companies have sprung offering cheapest services. For businesses, several service providers and equipment vendors are offering their services to replace old telephony infrastructure with new VoIP enabled infrastructure with Quality of Service (QoS) comparable with legacy PSTN.

 Use of VoIP for businesses has offered not only the reduction in costs but also improved customer services due to its features and applications that enable productivity gain. However, the complexity of VoIP system and sensitivity to quality of service makes it a difficult to choose the right VoIP telephony system. A wrong choice may result in loss of profits, wastage of time and money, and bad reputation to the businesses that depend on communications to provide customer services.

The VoIP offers far more than legacy PSTN system. It is highly flexible and can be used from anywhere if a broadband internet connection is available. You can even install VoIP software to enable a PC or a Laptop with microphone and headphone to act as a telephone with more advance features like voice mail, a fax, to have a virtual number independent of geographical that can be called from another number like a local number.

Technologically, VoIP uses a common infrastructure already existing for internet. Unlike legacy PSTN, it does not require dedicated network for travelling of calls over it, thereby enabling service providers to make best use of available network. Although the legacy PSTN has a shared network between Central Offices (PSTN Switches) but for each call a dedicated path is to be established serving only the call for which it was established. When two people are speaking on phone, there are lots of silent times. The study has established that a dedicated path for a call is actually used for only 40 % of total call time. Hence, any mechanism that could increase utilization of this path can save costs to service provider. Normally a PSTN path (channel for one call) uses bandwidth of 64 Kbps. Further research has resulted in development of voice coding methods that allow a call to use one fourth of bandwidth used by legacy PSTN call. VoIP systems can use bandwidth less than 16 Kbps for one call, thus increasing efficiency of available network capacity and hence reducing the cost.

 Large telecommunication service providers are also migrating to VoIP to compete with cheap VoIP service providers. Instead of completely replacing existing PSTN infrastructure, large Telco’s are investing in hybrid infrastructure that can utilize PSTN infrastructure as well for provision of cheap telecommunication services.