The possibility of voice communications traveling over the internet, rather than the PSTN, first became a reality in February 1995 when Vocaltec, Inc introduced its internet phone software. Designed to run on a 486/33-MHz ( or higher ) personal computer equipped with a sound card, speakers, microphone, and modem the software compresses the voice signal and translates it into IP packets for transmission over the internet. This PC to PC internet telephony works, however, only if both parties are using internet phone software.
Internet telephony has advanced rapidly. Many software developers now offer PC telephony software but, more importantly, gateway servers are emerging to act as an interface between the internet and the PSTN. Equipped with voice-processing cards, these gateway servers enable users to communicate via standard telephones.
Internet telephony has advanced rapidly. Many software developers now offer PC telephony software but, more importantly, gateway servers are emerging to act as an interface between the internet and the PSTN. Equipped with voice-processing cards, these gateway servers enable users to communicate via standard telephones.
A call goes over the local PSTN network to the nearest gateway server, which digitizes the analog voice signal, compresses it into IP packets and moves it onto the internet for transport to a gateway at the receiving end.
