CIRCUIT SWITCH TECHNOLOGY (PSTN):



Historically, telecommunications companies have relied on what is commonly referred to as ‘circuit-switched technology’ to transport telephone calls. This technology establishes a 'permanent' connection between the calling and the receiving parties for the entire duration of the call.

The problem with circuit-switched technology is that it requires a significant amount of bandwidth dedicated to each call, and it can only support certain types of calls (i.e. telephone to telephone). Moreover, the hardware needed to run circuit-switched networks is very expensive due, in large part, to the fact that voice and data services must be carried by different wires and thus need separate hardware to accommodate the two types of traffic. The higher cost of the hardware has caused many traditional telephone companies to resort to using parts of the Internet infrastructure to connect PSTN calls. You may have already placed or received a call using VoIP technology without even knowing it.

Naturally, the traditional telephone companies pass along the costs of building and maintaining a circuit-switched network to the consumer in the form of higher rates for their telephone services. Telecom companies may save some money by borrowing from Internet bandwidth, but if your call is placed on a regular telephone using PSTN hardware you won't see those savings.

VoIP TECHNOLOGY:



As the name implies, VoIP refers to calls that traverse networks using Internet Protocol (IP). This may mean that the calls are going over the Internet, or it may simply mean that calls are traveling over privately managed data networks that are using IP to transport the calls from one location to the other.

The voice stream is broken down into packets, compressed, and sent toward its final destination by various routes (as opposed to establishing a 'permanent' connection for the duration of the call), depending on the most efficient paths given network congestion.

At the receiving end, the packets are reassembled, decompressed, and converted back into a voice stream by various hardware and software elements. Whether the call originated on a PC, telephone, or an Integrated Access Device (IAD), and whether it is going to be terminated on a PC, telephone, or IAD, will determine the type of software and hardware needed to initiate and complete the call. Over the years, broadband phone company providers have been working on improving and re-engineering the hardware and software used in VoIP calls. Today you can compare a VoIP provider’s voice-quality to the traditional circuit-switched technology and find that the VoIP provider’s quality is comparable and often superior. VoIP services and features have also evolved and allow customers many new and exciting options, such as online account management, three-way calling, call forwarding, and extra/virtual numbers.

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