Monday, February 21, 2005

Voice Over Whatever

Telephone communication was once limited to heavy desk phones with dials that came in any color you wanted as long as it was black. They were permanently wired to the wall because only authorized telephone company service personnel were going to repair or move them. No way that YOU were ever going to exchange them for something else. There wasn't anything else.

Things have changed, right? Now there's a shooting war in progress between old and new telecom technologies with new and ever more exotic players jumping in all the time. With voice over this and voice over that, how do you know what to pick at all?

Lets take a look at some of the more popular legacy and emerging technologies and what they do:

Analog Phone: Also known as POTS for plain old telephone service. Sounds dull, doesn't it? It may still be your best choice for a single business line or a few lines with a key telephone system or small PBX. The latest wrinkle is bundling local and long distance service for a special price, or even including DSL Internet service in the package.

Voice Over TDM: Also known as digital trunking, T1, PRI, or Integrated T1 service. You don't plug phones into this type of service. It connects through a PBX interface. Your phone works the same whether the line to the phone company is analog or digital. But if you have more than half a dozen phone lines plus company Internet service, you might be able to save on your monthly telecom bill with this option. If you have more than a dozen phone lines and are still using analog, digital service can almost certainly save you money.

Voice Over IP: People like to call this "vOYp". With VoIP your analog phone is replaced by a digital phone and a network connection, same as a computer. That's what it is. Your phone has been taught to speak computer language, in particular IP or Internet Protocol. At the local network level the connection is known as Ethernet. One advantage of VoIP is that computer and telephone networks can be merged into one network since all the equipment speaks the same language. A possible problem is not having a fast enough network to handle both, with the phone conversations usually more affected than the data. Probably the biggest advantage of IP over other network standards is that it is quickly becoming THE network standard. If you want Internet telephony, VoIP is the way to go.

VoFR: Voice over Frame Relay offers a way to make phone calls on a private frame relay network. Many larger companies use frame relay networks to interconnect their various offices and plant sites. Like VoIP, VoFR can be used to share an existing computer network with telephone traffic. Since frame relay networks are private networks, you have more control over call quality than on a public medium like the Internet.

VoATM: No, you don't go to the ATM machine to make a phone call. In this case ATM stands for Asynchronous Transfer Mode. It's a private networking standard something like frame relay. ATM is designed around small cells of uniform size. This design is compatible up to and including optical carrier networks, which offer massive amounts of bandwidth from location to location. Traffic engineering features of ATM networks make quality of service for telephone calls fairly easy to achieve. Many of the well known long distance carriers use ATM as a transmission standard in their own national and international networks.

VoWiFi: Voice over Wi-Fi is a fast emerging technology that lets you make telephone calls at WiFi hotspots. Savvy computer users have been able to do this for a long time using "soft phones" which are software programs running on their laptop computers. If you don't fancy lugging around your computer to make phone calls, you'll soon find cell phones that also work on WiFi or perhaps special WiFi only phones. The technology has a ways to go yet before you can maintain a call as you move from hotspot to hotspot. A more advanced design will let your phone switch seamlessly from cellular to WiFi, depending on which is the best choice for wherever you happen to be.

VoWiMAX: Voice over WiMAX is a more powerful longer range version of VoWiFi that's not ready for prime time yet. When WiMAX becomes generally available in a couple of years, it might just give cellular a run for its money.

Cellular: This is the wireless phone system that is almost universally available for fixed location or mobile use. There are multiple standards worldwide, although you can get world phones that handle just about any cell network. Cell phones that combine voice, PDAs and BlackBerry text transmission are altering our notion of what a telephone really is. When VoWiFi and VoWiMax capabilities are included, it will be possible to integrate the cell phone into the corporate telephone system including PBX features like transfers, forwarding, conferencing, receptionist control and 3 or 4 digit dialing.


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