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VoIP Basics



by Ruchi Gupta

Have we ever realized how much will be benefited by VoIP technology? Personally I am very thankful to VoIP, as I am (staying in US) far from my parents and in-laws, but I can talk to them in India for about half an hour or more (depends on them and me), without costing so much. Simply we need computer, sound card, speakers and microphone.

What is VoIP anyway? If you are new to VoIP and want to get basic understanding of how it works, how will you get benefited by VoIP solution as a customer then this article is for you.

Let's get started. VoIP is a technology that allows us to make phone calls over a broadband Internet connection as opposed to traditional analog phone lines. In simple terms it makes our computer or laptop as telephone.

How does VoIP work? Before going to basics of VoIP technology, lets take a look on how our 100-year-old traditional telephone system works.

Traditional telephone system works on circuit switching, means when a call is made a connection is set up between source and destination, in both directions, and it is maintained till duration of call. This is a dual directional i.e. we are connecting two ports in both directions, so it will make a circuit.

There is one drawback in this system, i.e. the telephone line cannot distinguish between useful talking and silence. Like if conversation is going on between two persons then one will be talking and other will be silent, so half of the transmission data is wasted in this case. Apart from this, there are many instances when there is pause between conversation that silence is also treated as data and its transmission is a waste. So if we can handle these two issues that is if we can transmit only useful data and remove unwanted instances then we can cut data transmission by more then half.

VoIP technology took care of this drawback, so it uses packet switching, in this case it opens connection just long enough to send bits of useful data called packet from one system to another. This scenario is same as your computer is making connection to any website, as and when it is required, otherwise internet connection will be very slow, if it will constantly maintain connection with any web page.

This type of system allows the network to send our call (in packet) along the least congested and cheapest line available, we can say that about 3 to 4 calls from a VoIP system could fit in the space of our call from a circuit switch system. This is the basic reason why VoIP is cheaper then conventional calling plans.

There are different types of VoIP calling some of them are mentioned below.

  • ATA (Analog Telephone Adaptor) this adaptor enables us to make use of standard telephone for VoIP options, it actually allows to connect phone that is already at our home to our computer internet connection .ATA converts analog signal to digital signal, that can be easily transmitted through internet.
  • The next type of calling is through IP phones; they look just like our normal phones with same buttons. This only difference is they replace old style wall jack connector with Ethernet connectors, so it gets plugged directly into the router.
  • The most common type of calling is from computer-to-computer. This is the simplest and cheapest way to use VoIP. These calls are entirely free, only thing you need software that you can download from Internet, a broadband or DSL connection, microphone, speaker and sound card.
  • The latest technology that is emerging in the market and gaining popularity is Wi-Fi phones. This hybrid-Phone let people make connections using a local wireless Internet access point seamlessly switch over to a cell network whenever necessary.

Other than saving money there are more benefits from using VoIP system. What all benefits you get depend on provider also, some of the benefits are listed below.

  • Much cheaper long distance and international calls.
  • Many features (depends on provider) like Email alert for new voicemail, web access to voicemail, auto forward, caller ID, call waiting caller ID, call forwarding etc.
  • Flexibility, some explanation needed here. When we use VoIP phone service, our phone number is programmed into the converter, so we can take our converter and phone number anywhere in the world we want. As long as we have access to Internet connection we can use our phone number. We have option to choose area code for our phone number. Some providers allow us to have more then one phone number in different area codes, this means we get extra numbers that rings the same phone. These numbers are known as Virtual Phone Numbers. One advantage here is these numbers are local number to any area code; here we will be saving money. How? Suppose you go to some other city where you have many friends and family then they can call you on a local number, instead of paying for long distance charges to contact us.

There are many providers in the market with their own strength. As the technology is growing fast and incredible amount of work is dedicated to VoIP, some of the disadvantages that are associated with VoIP are going to resolve within next few years, it is expected that after some time VoIP will have widespread consumer acceptance.




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Mon Apr 17 13:42:41 2006: 1929   BigDumbDinosaur


There is one drawback in this system, i.e. the telephone line cannot distinguish between useful talking and silence. Like if conversation is going on between two persons then one will be talking and other will be silent, so half of the transmission data is wasted in this case.

This is primarily the case with the central office (CO) subscriber loop, but is not true anymore on long-distance (inter-LATA) trunks, which are virtual circuits running on fiber-optic links or similar high speed data paths.

VoIP technology took care of this drawback, so it uses packet switching...

Actually, it was the development of time division multiplexing (TDM) in the 1960's that introduced the concept of packet switched phone conversations. Originally applied to handling conversations through underseas cables, TDM's later application to land-line connections is what led to a huge jump in inter-LATA trunk capacity in the 1970's. Most importantly, TDM made trunk connections data-agnostic, allowing both conversation and computer data to flow at the same time.

This type of system allows the network to send our call (in packet) along the least congested and cheapest line available, we can say that about 3 to 4 calls from a VoIP system could fit in the space of our call from a circuit switch system...

This was already happening with analog voice connections over inter-LATA trunks, so VoIP didn't introduce anything new, except the use of a CATV link for the subscriber loop, the latter being a dubious improvement, given the poor quality of service provided by many cable TV operators.

...This is the basic reason why VoIP is cheaper then conventional calling plans.

I'd have to differ on this. VoIP is cheaper because it is an unregulated service, thus avoiding some of the costs associated with dealing with state commerce commissions and other trappings of government bureaucracy -- although I'm sure this will change. The other principle reason for the lower cost is that VoIP providers do not have the burden of building and maintaining the physical data links. Theirs is a virtual world built upon the physical world of the inter-LATA carriers who made the major investment in the trunk circuits, associated hardware, and people needed to run them. That too will change once the inter-LATA carriers start to lose business to the VoIP crowd.

Many features...auto forward, caller ID, call waiting caller ID, call forwarding etc.

All of which are already available from traditional carriers, since the technology to provide such features existed before VoIP came on the scene.

Flexibility...our phone number is programmed into the converter, so we can take our converter and phone number anywhere in the world we want.

This is the one real advantage of VoIP, since the phone itself is not physically tied to a CO subscriber loop. For a road-warrior who travels abroad at regular intervals this can be a real boon. Consider, however, that a cell phone user (considering currently available plans) has similar flexibility and doesn't have to drag a box and a regular phone around. For someone who seldom goes out of town (that would be yours truly), VoIP's number portability would be of no advantage. A cell phone takes up less space and doesn't need a broadband or DSL connection to work.

Some providers allow us to have more then one phone number in different area codes, this means we get extra numbers that rings the same phone.

Again, nothing that was invented by VoIP. Traditional carriers have offered this feature for a number of years.

A while back, I gave some consideration to switching my business to VoIP (which I did not do). In the process I identified some aspects of VoIP that you might want to consider before making the leap:

* The CO subscriber loop is replaced with your broadband connection. Broadband is one of the least reliable of data services currently available. If the broadband fails (which happens around here at least once or twice a week) VoIP will fail and you will have no phone service, not good if you are a business! Also, you won't be able to call the broadband provider to advise them of the service outage.

* Broadband is a shared medium. The ability to deliver VoIP packets in a timely fashion will deteriorate as more subscribers get on line. That is, your VoIP packets will be competing for bandwidth with packets going to other computers, which can lead to conversation dropouts.

* VoIP providers are not responsible for the actual data links. You will be dealing with more than one entity if a service outage occurs, and you may find it difficult to determine exactly why you don't have service and who you should contact to resolve the issue.

* VoIP is not as cheap as one might think. A cost often overlooked is that of providing broadband service, which is a requirement to get VoIP. Unless you make a lot of international calls, the combined cost of VoIP and broadband will probably be more than for traditional service (it was in our case, which is why I didn't go with VoIP).

* Local power failure will disrupt phone service. Conventional phones (not cordless ones) do not require the availability of local AC power to operate. VoIP does -- something has to power the ATA and broadband modem. If yours is a situation where phone service must work regardless of power failure (e.g., because of a resident in your home with a precarious medical condition), VoIP is not a good idea, unless you are also willing to invest in a standby power system to support your VoIP hardware.



Mon Apr 17 16:21:54 2006: 1930   TonyLawrence

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I would also opine that I doubt the price advantage will remain much longer..





Tue Apr 18 14:40:12 2006: 1933   BigDumbDInosaur


I would also opine that I doubt the price advantage will remain much longer.

Right you are, I'd say. When I was considering VoIP for my business it really came down to the cost. There just wasn't enough of a savings to justify a change. I figured that eventually the realities of the market would catch up with the VoIP providers and they'd have to charge more to stay profitable.

The other thing was reliability. At least in the USA and Canada, traditional phone service is very reliable -- I can't recall the last time we had a service outage here. For a business, reliable phone service is more important than cheap service. You can always charge a little more if need be to cover the cost of phone service. However, you can't charge anything if your clients can't contact you to hire your services.



Tue Apr 18 15:48:29 2006: 1934   TonyLawrence

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I am using it (through Comcast) for my home phone, but we also have two cell phones. It isn't much less money than Verizon would be, but it is a small savings.

We had a lot of trouble with it the first few weeks, but they got it straightened out.







Wed Apr 19 19:43:18 2006: 1939   gruchi01


Hi,
As I mentioned in my article "As the technology is growing fast and incredible amount of work is dedicated to VoIP, some of the disadvantages that are associated with VoIP are going to resolve within next few years, it is expected that after some time VoIP will have widespread consumer acceptance."
Its not fair to consider VoIP as very mature...but in coming years it is going to take wide consumer acceptance.







Thu Apr 20 04:50:40 2006: 1944   BigDumbDInosaur


...but in coming years it is going to take wide consumer acceptance.

I can see it being adopted for home use by those who make a lot of long-distance calls, especially overseas. Those who mostly make local calls won't see a savings in our area, as basic residential service with local toll calling is cheaper than VoIP (especially after you factor in the money that would have to be spent to get broadband or DSL to support VoIP). In any case, you can be sure that the traditonal carriers are not going to stand around looking stupid while they lose business to the VoIP providers. They (the traditional carriers) will adapt and achieve price parity.

As I said earlier, VoIP made no business sense to me. I seldom make long distance calls and with our broadband service being flaky, I envisioned reliability issues. My monthly business phone costs simply aren't high enough right now to justify switching to something that is less reliable.



Tue Mar 10 14:41:58 2009: 5640   TonyLawrence

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We dropped it later - Internet went down for half a day and of course took phone with it.

I can't afford to lose both at once. We went back to Verizon.



Mon Jun 1 18:57:08 2009: 6432   Andrewjones
http://www.voipsipsdk.com
gravatar
It's a well written article.It is more prevelant these days.Hence,it should be tried out..

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