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CDPD Still Holds Promise

Growth of Internet use makes Cellular Digital Packet Data’s future bright.

John Bendel
Senior Editor

CDPD. A few years ago, it was the hottest technology around, the wave of the future. But for the trucking industry, at least, the future never quite arrived. CDPD hasn’t gone away. In fact, its use has continued to grow, though not as rapidly as once predicted. But the increasing role of the Internet in trucking technologies could put CDPD back on the fast track.

NEW LIFE FOR OLD SYSTEMS
     It stands for Cellular Digital Packet Data, a technological mouthful that adds up to a way for older analog cellular telephone networks to compete with younger digital upstarts.
     CDPD means more than that, of course. Among other things, it means seamless connectivity to the Internet and, some say, faster data exchange. But CDPD’s original reason for being was to breathe new life into old networks.
     You may not think of the breakthrough cellular telephone networks built in the 1980s as old, but in terms of the current technology explosion, they are. Today a year is a long time, five years a very long time and 10 years eternity itself. But that’s how old some cellular networks are. And as all the ads for new digital systems constantly remind us, they are analog.
     Some people debate the quality of voice transmissions. Analog loyalists insist analog is superior. Digital supporters say the opposite. But in business where data transmission is involved, where supply chain logistics demand constant tracking, where it may be vital to have a signature transmitted instantly, there is no debate at all. Digital is better.
     Transmitting data over analog systems takes longer and requires extra steps. For example, you need modems to convert digital data and images into analog telephone signals, then back again.
     That’s where CDPD comes in. Though it operates across the analog structure and shares analog radio spectrum, it is purely digital. It can be used in conjunction with its host analog phone system or entirely on its own, and CDPD believers say it is faster and more adaptable than its proprietary wireless competitors.

BIG PROMISE, SLOW START
     Yet since CDPD was first introduced in the early 1990s, it has failed to make the inroads that had been predicted. The wireless data market did not rush to CDPD, despite clear advantages over rival technologies.
     For the moment, other technologies such as Ardis and Mobitex still have the lion’s share of a small-but-growing list of truckers using wireless data systems. Indeed, CDPD is still unavailable or very limited in many markets, and some competitors predict that new digital telephone networks will eventually kill off the analog networks on which CDPD relies, and CDPD itself will disappear.
     But the case for CDPD is strong and growing stronger. In the first place, say many industry observers, the analog networks are not about to disappear. They will provide a valuable service for a long time to come, and as use of CDPD grows, it will make those networks even more valuable.
     And there are good reasons CDPD will probably provide more, not less, competition to its proprietary rivals. That’s because CDPD is not proprietary but an open specification that supports, among other things, IP (Internet Protocol) — the universal computer language of the Internet. If any element of trucking technology is bound to grow, it is use of the Internet.
     Trucking applications and services making use of the Internet have proliferated in the last year alone, and there is much more to come. As a result, systems developers who must link with the Internet will lean toward CDPD over proprietary wireless systems requiring more complex interfaces. New CDPD applications and customers will pressure telephone networks to make CDPD increasingly available.

ROLLING OUT CDPD
     That’s the real hangup. Adding CDPD to an analog network isn’t as easy as throwing a switch at company headquarters. Building in CDPD capability is a big job that begins with reassigning to CDPD a portion of the radio frequency (RF) spectrum used between cell phones and cellular towers. It is a physical job that must be done at every individual cellular tower where CDPD will be available.
     Thus the smaller the area in which CDPD is used, the easier (and cheaper) it is to install. Phone companies have been reluctant to make the change over broad areas without being guaranteed at least a minimum of usage beforehand.
     That’s why — so far at least — CDPD has been far more popular with local law enforcement agencies than with truckers. Police departments tend to stay within limited geographical areas served by relatively few cellular towers. Even in the dense New York City area, Bell Atlantic revamped its Long Island towers only after receiving a commitment from a metropolitan area courier who wanted CDPD for data transmission.
     But increasingly, truckers are using the Internet for electronic data interchange (EDI), vehicle tracking, load finding and fuel management, among many applications. There are more Internet applications to come, and that probably means a brighter future for CDPD wherever it’s available.

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Packet Data and Networks