The Pros and Cons of VOIP

by [Published on 2 Aug. 2006 / Last Updated on 2 Aug. 2006]

As great as VOIP is, it is important to understand both the advantages and the disadvantages before investing.

When it comes to Web based applications, few hold more promise than Voice Over IP (VOIP). VOIP allows businesses and consumers alike to save astronomical amounts of money on their phone bills by routing phone calls over the Internet. As great as this technology is though, it does have its disadvantages. Before you blindly invest in a VOIP phone system, it is important to understand both the advantages and the disadvantages of VOIP.

The Advantages

There are so many advantages to using VOIP that I almost don’t even know where to begin. By far the biggest advantage to using VOIP is the cost savings. There are a lot of different VOIP systems available and the amount of money that you will save really just depends on which system you invest in. Some VOIP systems will only allow you to make calls to others who are running VOIP, while other VOIP systems will allow you to call anyone who has a phone. Typically, PC to PC VOIP calls are free, aside from the initial cost of the software and a possible monthly service fee. PC to phone calls typically cost more than PC to PC calls, but are still usually less than half of the cost of phone to phone calls. Most VOIP providers who support PC to phone calls charge a small monthly fee for unlimited calls within the United States. A very small premium typically applies to international calls.

As you can see, the cost of VOIP service really just depends on your service provider. The same can be said of the calling features. Most service providers include features such as call forwarding, call waiting, and three way calling with their VOIP service. These are far from being the only available features though.

Some VOIP services are computer based, meaning that you speak through a microphone that is connected to a computer. Computer based VOIP environments tend to be highly collaborative. It is not at all uncommon for a computer based VOIP system to be able to transmit video in addition to voice so that you can see and hear the person that you are talking to. Computer based VOIP systems often also allow you to share data and / or applications with the person that you are talking to, thus allowing collaboration on a project. Of course there is no reason why these collaborative sessions have to be limited to two people. Most computer based VOIP systems support conference calling.

Not all VOIP systems require the use of a computer though. Some simply use a digital VOIP phone or a VOIP adapter that can be used with a regular telephone. There are several advantages to using a VOIP phone rather than a computer based VOIP application. Probably the biggest advantage is simplicity. Placing a VOIP call over a VOIP phone is usually no more complicated than placing a normal phone call.

Another advantage is portability. A VOIP phone has an address built into it that is unique to your phone. This means that in most cases, you can take your VOIP phone with you and use it anywhere that a broadband Internet connection is available. Obviously, there are exceptions, but generally speaking you could take your VOIP phone with you on a trip to California even if your service was based in New York.

You don’t necessarily need a VOIP phone to get portability. Some providers of computer based VOIP services offer a Web interface. This interface allows customers to log in and place calls from anywhere in the world, so long as a broadband Internet connection is available. This should be a serious consideration if you have employees that travel a lot and make a lot of calls from the road. The service isn’t as convenient as a cell phone, but it is usually a whole lot less expensive and it works in foreign countries where a cell phone may not.

Disadvantages

As great as VOIP technology is, there are some major disadvantages that you have to consider prior to investing in VOIP. The biggest issue plaguing VOIP is sound quality. Don’t get me wrong though, with sufficient bandwidth and good equipment, it is possible to get fairly good sound quality from a VOIP system. In real world conditions though, there are no guarantees that the sound quality will be acceptable.

There are a couple of different reasons for the sound quality issue. The first reason has to do with the way that VOIP works. As I mentioned earlier, VOIP stands for Voice Over IP. To see how this can be a problem, think about how an IP network works in regards to transmitting data. When a file needs to be sent over an IP network from point A to point B, the file is broken up into a series of packets. The packets are transmitted in a sequential order, but because of the distributed nature of the Internet, the packets may arrive at their destination in order, or they may be out of order. Normally, this isn’t a problem because the recipient is able to use the packet’s sequence number to figure out what order the packets go in, and reassemble the data.

VOIP converts voice into digital data, which is then placed into packets and transmitted over the internet. As with any other type of data, these packets may or may not be in the correct order when the recipient receives them. The recipient’s VOIP system can reassemble the packets regardless of what order they arrive in. However, the real time nature of voice conversations means that if the packets arrive out of order, then it could result in a second or two of silence while the data is reassembled.

As you can see, latency issues can cause some major issues for VOIP systems. Data must be able to travel to the recipient quickly enough that it can be reassembled before anyone notices a significant delay. Since a lack of available bandwidth can cause such problems for VOIP systems, VOIP manufacturers have taken steps to reduce bandwidth requirements. Specifically, bandwidth requirements have been reduced through the use of various compression algorithms. However, these compression algorithms have caused some problems of their own.

One problem is compatibility. When it comes to PC to PC VOIP calls, there is no one universal standard. Some VOIP systems are proprietary in nature, and will only allow calls to others who are using the same software.

Another problem with compression is that compression (and decompression) consumes extra processing power. Furthermore, compressing the data tends to further degrade sound quality. Some compression algorithms have actually been known to cause problems with echoes. These echoes can be filtered out, but doing so requires even more processing power. Compressing and filtering data is more of an issue for computer based VOIP than for VOIP phones. VOIP phones handle the necessary compression and / or filtering at the hardware level. The advantage of this is that you never have to think about how much processing power your VOIP phone has, but it does mean that a VOIP phone can be more expensive than a regular phone.

Aside from the various sound quality issues, there are also a few practicality issues that you need to consider. For example, if you are considering a computer based VOIP system, then you must remember that you will not be able to place or receive calls unless the computer is turned on, and the VOIP software is running.

Another practicality issue is that unlike a traditional phone, a VOIP system (computer or VOIP phone based) is useless during a power outage. A traditional phone can function even during a power outage because the phone company transmits electricity over the phone line. This electricity is used to power the phone (cordless phones being the exception). That way, even if the power goes out, the phone will usually still work because the phone’s power is coming from a different source.

VOIP works completely differently though. A VOIP phone (or a computer based VOIP system) requires external power to function. Furthermore, a VOIP system also requires the Internet to be available. Therefore, if you lose power, or if you lose Internet connectivity, VOIP will not work.

One last issue that I want to mention is that the 911 service does not work properly over a VOIP phone system. Normally, when you dial 911, the phone company looks at either your phone number (if you are using a land line) or the cell tower that you are communicating through, and uses that information to put you in contact with the nearest 911 dispatcher. With VOIP systems however, the caller’s location cannot be determined through traditional means. As such, dialing 911 from a VOIP system won’t likely put you in contact with a local 911 dispatcher.

I have recently read about an experimental program which may eventually allow VOIP calls to be routed to the correct 911 dispatcher. The concept works by looking at the caller’s IP address. The reason that this is possible is because IP addresses are distributed based on geographic area.

Conclusion

As you can see, there are a number of negative issues associated with using VOIP systems. Even so, I fully expect these issues to become a thing of the past as VOIP technology matures.

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