Devices for IP telephony
In our
last
installment, we were talking about devices that can capture voice traffic and
immediately packetize it for transmission on a LAN or across the Internet. We noted
three types:
- A handset, headset, or tabletop microphone and speakers attached to a PC, with a
keyboard and mouse interface; - An adapter that mediates between an analog telephone and an IP network connection;
and - A standalone IP- or IP/PSTN-ready telephone (PSTN is the public switched telephone
network that connects ordinary telephones around the world)
The first category offers the greatest number of choices. VoIP product databases,
like Gecko
Research and Publishing's IpxStream,
Kuthan's list, and Internet Product Watch list dozens of software applications
for use with any Windows personal computer or Unix machine with access to an IP
network.
The bulk of the software applications for VoIP are available for download on the
Internet. Some require payment if you decide to keep them. To be useful, the software
on your PC must register with some sort of directory, so that people calling you don't
have to enter your IP address every time they want to call you. The latter situation
would be especially awkward if, like most dial-up users, you have a new IP address
assigned each time you connect to the Internet.
With each application, all users register automatically in a common directory
service each time the application connects to the network, and the directory service
resolves addresses on behalf of users. Generally, these directory services are not
public in the way our PSTN directory assistance is accessible from any end point. They
are available only to subscribers and are populated only with information about other
subscribers using the same service.
With any software, you'll need a voice-capture device. A simple microphone and
speakers plugged into a sound card should work fine, but if you want more convenience
or privacy, you can connect a handset or headset instead.
high-quality, PC-ready headset. Both are available in retail outlets and online
stores.
Options 2 and 3 above are emerging technology. There are a few products in these
categories, ideal for early adopters and more appropriate for the small- and home-
office markets than large enterprise deployments.
The Aplio/Phone is a good
example of an adapter that mediates between a telephone and the Internet. It connects
to your telephone just like an answering machine. When you make a call, the Aplio/Phone
can reroute your call through the Internet instead of using a commercial long distance
service provider. There is a catch, though; the person you're talking to must also be
able to make H.323-compliant calls over the Internet. The best solution, the company
suggests, is for that person to use another Aplio/Phone.
InfoGear's iPhone is an
example of a standalone (non-PC) IP phone that integrates a variety of standard
business telephone services (hold, transfer, messaging) with email access and Web
surfing. Kyushu Matsushita Electric Industrial, a sister company of Panasonic,
announced at the international Consumer Electronics Show in Las Vegas earlier this year
that it is developing a telephone that can use either the PSTN or an IP telephony
network, depending on the user's preference. A button on the phone will determine
whether the call will connect to your local PSTN provider or the global
version of this device in the near future.
If you're considering putting VoIP on your LAN or using the public Internet for
making your next telephone call, you have many choices -- too many, in fact. We'll be
tracking each of the three categories defined here and reporting on how they evolve.
Meanwhile, start trying products yourself. The experiences they produce are
dramatically different, and you should have firsthand experience before choosing a
supplier on behalf of a large community of users.
» posted by abennett
ITworld.com
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