Reality check on wireless data services. (includes related articles)

There'll be plenty to choose from in wireless datacom. But will anyone be truly pleased?

Despite the confusion that surrounds wireless data communications, you really can buy the equipment and subscribe to the services that make mobile computer networking possible. A growing collection of products and services is available - from cellular modems to pagers, dedicated terminals in moving vehicles to hand-held computers with radio modems, and metropolitan-area to nationwide services.

The bad news is that the wireless data communications market is young, volatile and complex. Few products and services interoperate with one another, reflecting the ambitious attempts of various players - new startups, old die - hards hards and almost everyone in between - to win customers and influence further development. Most of these players also participate in one or more alliances, consortia and joint ventures to trumpet their visions and tout their wares.

Until the dust settles, determined customers will have to evaluate the benefits and limitations. of each solution. Whether you see current applications, or wireless data in your own organization, however, it's worth keeping up with the latest developments in several wireless market segments.

Analog Cellular Modems

The data and fax modems used with analog cellular phones aren't wireless: They require wired connections both to your cellular phone and to your portable computer. Nevertheless, this is one of the largest wireless data markets, not only in terms of total customers and service revenues, but also based on the many active vendors and available products.

According to BIS Strategic Decisions (Norwell, MA), 200,000 cellular phone customers used these modems to make an estimated $140 million worth of data calls last year. Leading vendors include AT&T Paradyne (Largo, FL), Data Race (San Antonio, TX) and Hayes Microcomputer Products (Norcross, GA), and the devices range in cost from about $200 to $700.

This last year saw several new cellular modems that fit into special, standard-sized slots on PC laptops. These Personal Computer Memory Card International Associations (PCMCIA) slots are about the size of a credit card and less than one-half-inch thick. Modem cards for the slots cost $300 or more, but prices are dropping fast. since there is a lot of competition among more than a dozen manufacturers.

There are three drawbacks to analog cellular modems:

* Attachment cost.

* Roaming.

* Reliability.

Unlike wired telephones, cellular phones don't have RJ-11 jacks. No two cellular phones have the same interface or plug, and each has specialized electronics that make plug-and-play impossible with a wide variety of modems. For example, AT&T Paradyne's KeepInTouch modem works only with the Nokia (Sausalito CA cellular phone.

Prices for the connecting cables are high - from $100 to $400. Data Race probably has the widest assortment of cables for the widest range of phones, including models from AT&T, OKI, SEC, Motorola and Pioneer. Prices are less than $200 for a cable connecting the phone to Data Race's PCMCIA card modem (RediCard).

Roaming and connection reliability are also troublesome. Only a few cellular service providers, notably GTE and Cellular One, have made their systems relatively easy for nationwide roamers to use. Reliability, while satisfactory for most voice calls, can pose problems for data when cellular signals fade or drop entirely as users move about.

These obstacles are not insurmountable, however, as evidenced by United Parcel Service (Paramus, NJ), the most …