Introduction to How VoIP Works If you’ve never heard of VoIP, get ready to change the way you think about long-distance phone calls. VoIP, or Voice over Internet Protocol, is a method for taking analogue audio signals, like the kind you hear when you talk on the phone, and turning them into digital data that can be transmitted over the Internet.
How is this useful? VoIP can turn a standard Internet connection into a way to place free phone calls. The practical upshot of this is that by using some of the free VoIP software that is available to make Internet phone calls, you’re bypassing the phone company (and its charges) entirely. VoIP is a technology that has the potential to completely rework the world’s phone systems. Above all else, VoIP is basically a clever “reinvention of the wheel.”
In this article, we’ll explore the principles behind VoIP, its applications and the potential of this emerging technology, which will more than likely one day replace the traditional phone system entirely.
The interesting thing about VoIP is that there is not just one way to place a call. There are three different “flavours” of VoIP service in common use today.
ATA — The simplest and most common way is through the use of a device called an ATA (analogue telephone adaptor). The ATA allows you to connect a standard phone to your computer or your Internet connection for use with VoIP. The ATA is an analogue-to-digital converter. It takes the analogue signal from your traditional phone and converts it into digital data for transmission over the Internet.
IP Phones — These specialized phones look just like normal phones with a handset, cradle and buttons. But instead of having the standard RJ-11 phone connectors, IP phones have an RJ-45 Ethernet connector. IP phones connect directly to your router and have all the hardware and software necessary right on board to handle the IP call. Wi-Fi phones allow subscribing callers to make VoIP calls from any Wi-Fi hot spot.
Computer-to-computer — This is certainly the easiest way to use VoIP. You don’t even have to pay for long-distance calls. There are several companies offering free or very low-cost software that you can use for this type of VoIP. All you need is the software, a microphone, speakers, a sound card and an Internet connection, preferably a fast one like you would get through a cable or DSL modem. Except for your normal monthly ISP fee, there is usually no charge for computer-to-computer calls, no matter the distance. If you’re interested in trying VoIP, then you should check out some of the free VoIP software available on the Internet. You should be able to download and set it up in about three to five minutes. Get a friend to download the software, too, and you can start tinkering with VoIP to get a feel for how it works.
Using VoIP Chances are good you’re already making VoIP calls any time you place a long-distance call. Phone companies use VoIP to streamline their networks. By routing thousands of phone calls through a circuit switch and into an IP gateway, they can seriously reduce the bandwidth they’re using for the long haul. Once the call is received by a gateway on the other side of the call, it’s decompressed, reassembled and routed to a local circuit switch. Although it will take some time, you can be sure that eventually all of the current circuit-switched networks will be replaced with packet-switching technology. IP telephony just makes sense, in terms of both economics and infrastructure requirements. More and more businesses are installing VoIP systems, and the technology will continue to grow in popularity as it makes its way into our homes. Perhaps the biggest draws to VoIP for the home users that are making the switch are price and flexibility. VoIP phone users can make calls from anywhere there’s a broadband connection. With VoIP, you can make a call from anywhere you have broadband connectivity. Since the IP phones or ATAs broadcast their info over the Internet, they can be administered by the provider anywhere there’s a connection. So business travellers can take their phones or ATAs with them on trips and always have access to their home phone. Another alternative is the softphone. A softphone is client software that loads the VoIP service onto your desktop or laptop. The Vonage softphone has an interface on your screen that looks like a traditional telephone. As long as you have a headset/microphone, you can place calls from your laptop anywhere in the broadband-connected world.
Advantages of Using VoIP
- It uses your LAN- An IP-PBX business phone system will reside on your network using your existing LAN. The PBX server is only a short distance away, so signaling distance and time (latency) is very short and does not depend on traveling over the Internet and other networks.
- Lower operational costs over time– In addition to taking advantage of lower cost VoIP routing, purchasing your own IP-PBX lowers costs over time. When using hosted VoIP the initial costs are most likely lower, but monthly subscription costs are ongoing and higher over time when compared to an IP-PBX. An business owned IP-PBX will usually result in lower averaged monthly operating costs especially for systems with a higher number of users.
- Easier to configure and install than proprietary phone systems- Proprietary phone systems can be cumbersome and difficult to navigate around their software to configure and install. An IP-PBX system will be much more familiar to computer savvy people, especially someone who has experience with networks. This can be especially true for Asterisk based systems that have a front-end GUI such as FreePBX.
- Simpler Management- The GUI of an IP-PBX will be much more user friendly than traditional PBXs. This allows for easier changes and additions.
- Easy to move phones- Because phones are IP based, they are like PCs, move them from one connection to another and they find home and connect right back up to the PBX server. No longer are the days when a simple phone move needs to have cross connects changed and a phone technician making a billable service call.
- Unified Messaging– Having the ability of receiving and listening to your messages from your Outlook inbox, along with PDFs of faxes increases communication and productivity. Integration with work applications, such a CRM packages can help business performance.
- Branch offices– can be added to an existing system and connected through an Internet connection. (Again lower cost, with the IP-phones being the major cost of the hardware needed.)
- Remote Extensions– employees can plug in a compatible IP- Phone at home to their Internet connection and be extension dialing.
- Cost savings by connecting to VoIP providers via SIP trunking- Using SIP trunking with an in house IP-PBX can connect to lower cost VoIP providers; reducing phone bills, especially long distance and International calls.
- More choices- Major companies that have built PBXs are now focused on IP connectivity, but even better are all the upstart companies that are building Asterisk IP-PBXs with lower prices and vendor neutral hardware.
Disadvantages of Using VoIP
- The current Public Switched Telephone Network is a robust and fairly bulletproof system for delivering phone calls. Phones just work, and we’ve all come to depend on that. On the other hand, computers, e-mail and other related devices are still kind of flaky. Let’s face it — few people really panic when their e-mail goes down for 30 minutes. It’s expected from time to time. On the other hand, a half hour of no dial tone can easily send people into a panic. So what the PSTN may lack in efficiency it more than makes up for in reliability. But the network that makes up the Internet is far more complex and therefore functions within a far greater margin of error. What this all adds up to is one of the major flaws in VoIP: reliability.
- First of all, VoIP is dependant on wall power. Your current phone runs on phantom power that is provided over the line from the central office. Even if your power goes out, your phone (unless it is a cordless) still works. With VoIP, no power means no phone. A stable power source must be created for VoIP.
- Another consideration is that many other systems in your home may be integrated into the phone line. Digital video recorders, digital subscription TV services and home security systems all use a standard phone line to do their thing. There’s currently no way to integrate these products with VoIP. The related industries are going to have to get together to make this work.
- Because VoIP uses an Internet connection, it’s susceptible to all the hiccups normally associated with broadband services. All of these factors affect call quality:
Latency Jitter Packet loss
- Phone conversations can become distorted, garbled or lost because of transmission errors. Some kind of stability in Internet data transfer needs to be guaranteed before VoIP could truly replace traditional phones.
- VoIP is susceptible to worms, viruses and hacking, although this is very rare and VoIP developers are working on VoIP encryption to counter this.
- Another issue associated with VoIP is having a phone system dependant on individual PCs of varying specifications and power. A call can be affected by processor drain. Let’s say you are chatting away on your softphone, and you decide to open a program that saps your processor. Quality loss will become immediately evident. In a worst case scenario, your system could crash in the middle of an important call. In VoIP, all phone calls are subject to the limitations of normal computer issues.
- One of the hurdles that was overcome some time ago was the conversion of the analogue audio signal your phone receives into packets of data. How it is that analogue audio is turned into packets for VoIP transmission? The answer is codecs.