IP Telephony 101: The Utter Beginner’s Guide

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Telephony. Sounds harmless enough.

First, a definition from Merriam-Webster: “the use or operation of an apparatus (as a telephone) for transmission of sounds as electrical signals between widely removed points.”

Gotcha. I’m with you. Me hear pretty, oll korrect.

Now let me just dip into my pile of telephony white papers, which I’ve been using as a doorstop until now (through no real fault of their own).

7 Steps to a Successful IP Telephony Implementation
What You Need to Know about VoIP
Voice over IP Reliability
How to Buy a Phone System
The Definitive Guide to Successful Deployment of VoIP and IP Telephony—Chapter 1
Voice over IP Manageability

Uh, IP telephony, right.

“IP” stands for Internet protocol, which is where the problems begin. I understand Internet. The protocol part, not so much.

From Wikipedia: “The Internet Protocol (IP) is a data-oriented protocol used for communicating data across a packet-switched internetwork.”

This is where I like to play a little game I like to call “ignore-all-the-words-I-don’t-understand,” which leaves me with this:

“The Internet… is… used for communicating data…”


So I did some research (see white papers above).

It turns out to be rather simple: IP telephony allows you to make phone calls over the Internet—including long-distance phone calls.

Which brings us straight to...

... the Pros and Cons of IP Telephony

The pros: IP telephony saves you long-distance charges. If you’re measuring your monthly phone bill in thousands of dollars, then that’s what you’ll save. It can also ease the burden of managing remote offices, for much the same reason.

The cons: Ever tried to recite the Magna Carta while your four-year-old son aims a vacuum cleaner at your mouth? No?

See, it’s like that—when your conversation consists of bits and bytes (which it does, if you’re talking over the Internet), and some of them suddenly disappear altogether (which they will, because the Internet’s really good at that if your infrastructure is shaky), then you can end up with some pretty choppy talk—or with calls that are dropped altogether. Can you really afford the inefficiencies and customer dissatisfaction that go along with that?

Help! There's an IP Telephony Product Brochure in My In-box!
Below are just a few of the terms that will come flying at you when you consult IP telephony product brochures. Rather than go haywire with geek-speak, I’ll simply give a simplified explanation of how they affect you, so you’re armed with a measure of understanding when the vendors come calling:

  • Bandwidth

The bandwidth (think of it as e-space) you allocate to your IP architecture will determine how many users can communicate simultaneously. The wider your bandwidth, the better the quality of communication.

  • Latency and jitter

Latency refers to the time it takes for your voice to get from your mouth to somebody else’s ear. Jitter, not surprisingly, refers to the sound quality of your voice. More jitter = bad.

  • Packet loss

A packet refers to the tidy, well, packet of data that carries your voice to its destination. Packet loss is not a good thing, and it often manifests itself as a “dropout” of sound.

So What Are My Options?
You get what you pay for. That may sound like a truism, but it’s especially pertinent to IP telephony. Stay tuned for IP Telephony 201, when I’ll explain why. We’ll cover the basics of IP telephony architecture (including the premise vs. hosted dilemma), common features of IP telephony systems, and how much you can expect to pay.

Can’t wait? Check out TEC’s IP telephony white papers now.
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