For well over a century, telephone access has been provided by public switched telephone networks (PSTN, also known as “POTS”), in which each call requires the dedicated use of an individual telephone circuit. Improvements have been made to this system to make it more efficient (such as digitizing the analog signals that carry voice traffic), but still, the system requires the use of dedicated circuits, and thus is inherently limited in the uses to which its potential bandwidth may be put.
Conventional PSTN has also proven itself to be ill-suited to providing the consumer with certain telecommunication features believed to be desirable at an affordable price-point. For example, while video phones have been available to the public since the early 1960's, they have achieved only modest market penetration in the business market, and very little in the consumer market.
The development of Internet Protocol networks, which makes far more efficient use of available bandwidth by packetizing data streams into data frames and transporting them along dynamically changing routes, has opened up the possibility of providing the consumer both with conventional voice-only telephone services and video telephony at very competitive prices. Typically, these services can be provided over Internet Protocol networks via Voice-over Internet Protocol (VoIP), the increasingly widespread acceptance of which has facilitated the broad roll-out of IP telephony products and services to the consumer. However, the commercial acceptance of such services depends not only on their cost, but also on their being easy to use and familiar to the consumer.
One area in which PSTN is particularly easy to use is in the use of extension telephones. When a user wishes to switch phones or join in on a conversation using an extension telephone, all that he must do is raise the handset from the hook. The commercial acceptance of VoIP telephony can be advanced by systems that are similarly transparent and easy for the consumer to use.