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Subtopic 2: Voice Over Internet Protocol (VoIP)

Make all the long distance phone calls you want for one low price!  Many broadband Internet providers are touting new services to make long distance bills a thing of the past.  Companies are foregoing traditional telephony service and opting to go with newer services that use network technologies to provide telephone service.  How are these things possible?   

Voice Over Internet Protocol  (VoIP) is a new technology that uses broadband Internet and/or network lines to transmit real-time voice information.  This technology has the potential for completely changing the way phone calls are made and making phone companies a thing of the past. 

To make a phone call on the Internet, several things must happen.  On the sending side, analog voice signals are digitized, compressed, divided into packets and transmitted over network lines.  On the receiving end, the signals are recombined, uncompressed and converted back into audio.  Because the voice signals are digital, they can be transmitted just like any other data packets on a network.  The major difference between these voice packets and regular data packets is that for VoIP to be effective, the signals must be delivered in a timely, reliable manner. VoIP can be relatively inexpensive to implement, although costs rise as the complexity of the system increases.  Because many companies already possess the infrastructure necessary to implement VoIP, more and more of them are opting to forego traditional phone service.  Cisco’s CEO John Chambers predicts that enterprise networks will accelerate their adoption of Voice over IP technology. (>

There are currently several problems with this technology.  If the computer or network lines fail, then telephone service is interrupted.  While the stability of computer hardware, operating systems and network infrastructure has improved significantly in the last decade, crashes still occur.  The "up" time of these systems is still significantly less than with traditional phone systems--which often continue to function even during power outages.   Another issue is that tracking the origin of a call is difficult because the signals are transmitted over the Internet.  This is especially important to emergency responders to 911 calls.  Caller ID service may not function either.  Additionally, devices that make calls using phone lines, such as fax machines, cable TV boxes, etc. may not function properly.  Law enforcement officials may have difficulty wiretapping phone lines that use VoIP technology.  Finally, the quality of VoIP service is lower than that of a traditional phone system.  Since the information is transmitted over network lines, it is subject to the same issues that other data streams experience including delays, packet loss and bandwidth availability.  Thus VoIP phone calls may break up, hesitate, or cause words to be dropped.  All of these issues are being addressed and their significance should be eliminated over time.


Further reading and research can be found at the following links: