Pronounced Packet Problems

It's hard to compare the sound quality of the systems we review here because the Internet doesn't cooperate. Most people who use these products will probably find that the quality of the channel carrying the packets is the most limiting part of the technology. No matter how good the software is, it can't do much when packets get lost or delayed along the way.

The real problem is that the Internet was never designed to handle communications, such as phone conversations, that are highly time-dependent. The network routes packets between two locations, but it can't guarantee that the packets will arrive in any predictable order or on any schedule.

If a packet disappears during a file transfer, it can be resent and the user won't notice the glitch. Most of the time, Internet connections are good enough to support a conversation, but there's no guarantee like the one you receive from the phone company when your telephone initiates a call.

For this reason, the sound quality of Internet phone calls depends on the state of the network at the particular time you call. In some telephone calls we made to Israel, voices were barely recognizable because so many packets were disappearing. The software did its best to reassemble the message with the packets that did make it through, but the speech was too clipped to make sense. Other phone calls--to Sweden, for instance--worked perfectly. The Internet is so decentralized that you simply can't count on the quality of any given connection.

For most people, for now, these phone products will be toys. It's fun to meet people from around the world and speak with them and not pay s ky-high phone bills, but the sound quality is too spotty for business conversations. And it's important to remember that the calls are free only because the Internet doesn't have any mechanism for billing based on traffic. This could change in the future.

People with access to better Internet links may consider using these phones as real devices. Some corporations, for instance, maintain their own WANs that link geographically dispersed offices. If these connections are fast, then better phone connections may be possible because you're not relying upon a common resource like the Internet.

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Lost Your Voice?

illustration_link (21 Kbytes)

A much simplified depiction of what happens when speech is converted into digital packets that are sent through a network and received out of order, with pieces missing. Since the original was created in real time, a missing packet can't be resent, thus creating a gap in the data stream, which the recipient hears as clipped words or run-together speech.