NWA-PCUG Newsletter Article, May 2005
VoIP (Voice over Internet Protocol)
by Brian K. Lewis, Ph.D.,
Member of the Sarasota Personal Computer Users Group, Inc.
http://www.spcug.org


Are you using the Internet for your local and/or long distance service? If not, then maybe you need to read this article to find out how some computer users are saving “mucho dinero” on their telephone calls.

VoIP stands for Voice over Internet Protocol. There are ways to use the Internet for free phone calls, low cost phone calls (2¢ per minute) or a monthly fixed rate for both local and long-distance calls. So how is it possible to transmit your voice over your Internet connection? We’ll look at some of the technical aspects first. Then I can discuss some of the services that are available for you to check out further.

When you use your telephone your voice is converted into electrical impulses and transmitted over copper wires to another phone. There it is converted back to sound waves. These impulses are transmitted via several switches in the telephone network. This system is referred to as the Public Switched Telephone Network (PSTN). As long as you are talking on the phone you have a constant circuit connection between the two phones. In the original PSTN system, all calls required a dedicated wire for each call. For the period of time you were on the phone you “owned” a copper wire connection between your phone and the other party. In today’s PSTN, all calls are digitized and can be combined with thousands of others running over fiber optic cable between central stations. However, the connection between the two phones must remain open for the length of the call.

When computer data is transmitted over phone lines or cable, it is also in digital form. However, the data is sent in packets and does not require a dedicated pathway to reach its destination. In fact, when a computer sends a stream of data packets, they may all arrive at their destination after traveling different routes. There are thousands of possible paths between any origin and any destination. In addition, packets from other origins can use any time spaces between your packets. This is a more efficient system, as a circuit does not need to be kept open. This system is referred to as packet switching.

So if your e-mail is being chopped up into small packets, how does the system know what to do with them? Each packet contains an address that tells the router what its final destination is. The sending computer sends the packet off to a router and then goes on to its next operation. The router selects a path to another router and sends the packet off. This process continues to the destination computer. At the destination, the receiving computer assembles the packets based on the information contained in each packet.

So what does this have to do with Internet phones? Very simple. VoIP uses the packet switching technology to transmit your call. The digitization of your voice occurs either through your sound card or a device known as an analog telephone adapter (ATA). There are also Internet phones which connect directly to a network router and handle the conversion process. The voice packets that result from these various adapters are routed over the Internet in the same way as data packets. When you make a phone call, there is always dead space when no one is talking. With the packet system, other data packets from other sources are being transmitted over the Internet making maximum use of its capacity.

In the early days of VoIP sound quality was poor and the method of operation more like using a walkie-talkie. Today’s equipment is vastly improved. Sound quality on many VoIP systems is the equivalent of that found in the PSTN. Depending on the system you are using, you can dial any number and your call will be routed over the Internet. In such a system, you and the party you called won’t see any difference in operation or sound from that of the PSTN.

So why would you be interested in using an Internet phone instead of your current local/long distance PSTN service? One big factor for many people is cost. The cost of Internet service ranges from free to $25/month (more in some cases) for unlimited calls. In addition, many of the VoIP services offer features that cost you extra through your local phone company. It is not unusual for a VoIP provider to include Caller ID, Call waiting, Call transfer, call forwarding, voicemail and three way calling as part of the basic price.

Now let’s look at some of the providers and their services. Skype (http://www.skype.com) offers a free service that allows you to connect to other Skype users. The software for this can be downloaded from their website. It took just a few minutes to install it on my computer. Once you have installed it, you need to setup a call list of other users. So you have to contact people that you call frequently and have them install the Skype software. From that point on, it becomes much like instant messaging. If the person you are calling is on-line, you can connect and talk to them. Otherwise, they have no way to know that you are calling. The reverse is also true if they want to call you. The minimum hardware you need for this are speakers connected to your sound card and a microphone. You can also use a headset with a built-in microphone. It is also advisable that you have a broadband connection, either cable or DSL. In my testing of it, once I had a connection, the call was quite clear with no background static or other problems.

So what do you do if you have Skype and want to call someone who doesn’t have Skype? You can get SkypeOut that allows you to call any phone number anywhere in the world for about 2¢/minute. After you install the SkypeOut software you buy credit on their Internet site which you can then use for your calls. Some reviewers have had sound problems with SkypeOut. I have not tested it.

There are other free services available as well. One is Free World Dialup (http://www.freeworldialup.com). This is a quote from their website: “FWD allows you to make free phone calls using any broadband connection using devices that follow Internet standards. This can be a 'regular' telephone connected to a packetizer, an IP Phone or any number of free soft-phones (software for your PC or PDA).” In order to use the system you need to download and install the software. Then you obtain a phone number from FWD. The hardware you need is a SIP compatible ATA adapter that you connect to a network router that connects to your modem. You can then connect any telephone to the jack in the ATA adapter. Now you’re ready to dial any FWD user anywhere in the world. However, you can not dial a regular PSTN phone from this system without purchasing time from another VoIP provider. The advantage of FWD over Skype is that your computer doesn’t have to be on to receive calls. Your phone will ring just as it did when connected to the PSTN phone system.

There is another advantage to FWD. This system uses the Session Initiation Protocol (SIP) standard. This allows FWD users to call others who are not member of FWD but are connected by a different SIP compatible service. Other free services currently using the SIP standard are IPTEL.org and SIPPhone.com. Skype does not adhere to the SIP standard.

Now we get to the services that charge a monthly fee. These providers furnish a SIP compatible ATA adapter and in some instances the router for your telephone connection. This list includes companies like AT&T (CallVantage), Verizon (VoiceWing), Packet8, VoicePulse and Vonage. Of these, AT&T and Verizon are the most expensive. Several of these providers are preparing wireless units that will allow you to connect through any WiFi hotspot. Vonage has announced that they expect to have a wireless unit available by mid-summer 2005. That means you could make and receive call while you are on the road. Also, by taking your ATA adapter with you when you travel, connections can be made through broadband data ports in many hotels and motels.

Of these providers, Vonage has been in the game longer than the others and has a strong reputation as to its quality. They have two basic plans: (1) $24.99 for unlimited calling in the U.S. and Canada, (2) $14.99 for 500 long-distance minutes. They also offer virtual phone numbers with any area code you prefer. Dialing other numbers in your area code requires just seven digits. You can add a fax line for $10 per month or toll-free numbers for $5 per month. With Vonage and these other providers, you can call any PSTN number or numbers on the FWD network. For more details on the specific services provided by these companies I would suggest you check their web sites.

So what are the drawbacks to VoIP services? First, if your Internet provider has a service outage, then your phone service is also down. Second, if there is a power outage you lose your phone service unless your system has a battery backup to keep it running. Another disadvantage is that most of these services can’t connect to 911. In some cases, you can call 911 after you have provided the service with location information for their files. They need this information so the system will know where to direct the call. However, the 911 operator can’t see your name or address and you have to provide that information when you make the call.

In spite of these disadvantages, VoIP usage is rapidly increasing. If you are interested in testing VoIP, I suggest you start with one of the free services. Try it, you may like it.

Click here to return to top



==================================================================