PDA upgrades:a recurring nightmare?

In today's PC world, it's reassuring to know that just about any desktop system you buy will have PCI-based expansion slots. In the notebook world, PC Card slots are standard fare. Because either type of computer has a bunch of standard connectors, if you decide to upgrade, many of hardware and software you already own can be re-used. The same cannot be said of personal digital assistants (PDAs).

Vendors who forced their customers to endure unnecessary expense along the upgrade path usually end up losing in the long run. For example, IBM paid dearly in terms of marketshare when it went one direction with its Microchannel architecture, and the rest of the industry went a different way. As an IT manager back then, I remember how fed-up my end users were when I told them they would have to spend another $700 on a new IRMA card (for connecting PCs to mainframes) because the PC they just bought didn't have the same bus type as the one they were replacing.

Today, PDA vendors --particularly the system vendors --don't seem to realize that they're repeating the mistakes of their PC predecessors,

Case in point: During the early to mid 1990s, I remained a Palm loyalist, even as the company kept changing its cradle interface. As a result, if you upgraded to a new Palm, you couldn't re-use the old cradle as a backup or for keeping one at work and one at home. The cradle issue wasn't totally intolerable, but when I decided to adapt my Palm V to a CDPD network, I unknowingly started down a path that would take me away from Palm.

To connect my Palm V to the wireless network, I purchased an expensive Minstrel wireless modem. It cost about $500 and it attached to the back of the Palm V in a way that used the device's cradle connector as well. Some people affectionately called this wireless modem "the sled" because, when attached, it looked like the Palm was riding a sled.

Subsequently, Palm introduced its next generation of PDAs with color. The company sent me an M505 to test, but it was incompatible with my sled. This created two problems. Not only couldn't I connect to my "old" CDPD network without getting a new CDPD modem, but a modem compatible with the M505 didn't exist yet.

By this time, Compaq had sent me one of its color display-based iPaqs. Since the modem sled was incompatible with the iPaq as well, connecting the device to the CDPD network would mean investing another $500 in a compatible modem. Either way, a new CDPD modem would be required. At that point, I switiched to the iPaq, mainly because a PC-card modem-- Sierra Wireless' AirCard 300--was already available for it. iPaqs can be expanded to use PC Cards (the same ones that go in notebook computers) with a special, sled-like adapter called a sleeve.

I've been using the same iPaq for the last year and half, with the sleeve and the Sierra Wireless AirCard 300 CDPD modem. Last fall, when a new round of PDAs appeared, I tested several of them. For $299 (after a $50 rebate), Dell's Axim, which has both a Compact Flash (CF) and an Secure Digital (SD) slot, is a great deal if you're starting from scratch. In my situation, I wanted to connect my PDA to the CDPD network and, reminiscent of the problem with the old sled and the new Palm handhelds, I would be forced to buy yet another modem that goes into the CF or SD slots. I couldn't even find one of those, which eliminated Dell's product from consideration.

Next up was HP's iPaq h545, which came with a replaceable battery, built-in support for Bluetooth, and a fingerprint scanner for device security. . Since the HP accepted the old PC Card-adapter sleeve and ran the same operating system as my old iPaq (PocketPC 2002) I figured that my Sierra Wireless AirCard 300 modem would work. Unfortunately, this is not the case. When I went to download the device driver software from Sierra's Web site, the following notice was posted in bold red:

"Sierra Wireless is aware of an incompatibility with the AirCard 300 and the HP iPAQ 5450 & 5455's. There are no plans to resolve this for the AirCard 300; however, the AirCard 550, 555, 710 and 750 are all compatible with the iPAQ 5400 series which run the Intel XScale processor."

Trumped again. How could this be? Isn't one point of the operating system (PocketPC 2002) to provide of layer of insulation from the hardware so that forward compatibility is maintained? Microsoft's rationale in standardizing on Intel's StrongArm (now XScale) processors for all PocketPCs was to guarantee software compatibility across all PocketPCs. Usually, software compatibility implies backwards, forwards, and vendor-to-vendor compatibility for applications as well as device drivers.

But not, apparently, in this case. A Sierra Wireless spokesperson explained the problem as follows: "It has been discovered that Intel's new XScale PXA250 processor, currently being used in several CE devices, including the iPAQ 3900 series, is unable to perform 8-bit reads from serially attached PC Cards when using the Dial Up Networking (UART) interface."

The implication was that Intel introduced an incompatible technology into PocketPC handhelds that the operating system couldn't smooth over and that developers couldn't handle. Intel's engineering department told me: "The PXA250 is fully compliant with the PCMCIA specification. Note the PXA250 is used in both the iPAQ39XX family and the iPAQ5450. Please direct PC Card issues with the iPaq to HP."

Next, I contacted HP. Mind you, I have the sort of access to these companies that mere mortals do not. In pointing out that it can't be HP's fault, HP spokesperson Sheila Kalra drew my attention to something that I should have noticed in the first place. Sierra Wireless is somehow supporting the PXA250 in the 3900 series of iPaqs, but not in the 5450. This seems to contradict the original excuse supplied by Sierra Wireless. Coming full circle, I went back to Sierra Wireless on February 26. The issue is still unresolved.

It's about time for he vendors of PDAs and their operating systems to do what the vendors of computers and their operating systems eventually did: guarantee a healthy dose of investment protection.

Until then, I guess I'll just stick to what I'm stuck with--my old iPaq. Bummer.

David Berlind is executive editor of ZDNet's Tech Update.