Hands on Review of pdQ Palm/Cellphone

hal-j writes "Ed Keyes, author of HackMaster for the Palm, has a hands on review of the way cool Qualcomm pdQ Palm/cellphone combo (which is now available)." For those who aren't paying attention, the pdQ is that half Palm III half Cell Phone mutant thing that actually looks quite interesting. Worth a gander.

Comments

And what about airplanes?

[srk]

Here is a potential problem for this type of the devices: As you know all cellphones has to be switched off while the airplane is in the air. I remember that not long ago there was an articles about one guy in UK who had got a year in prison for typing an e-mail message on his cellphone. The story was smth like this: a flight attendant asked that guy to switch off his phone but he refused saying that he is not using a phone but is just entering a message. In fact airplane is a very logical place to use a PDA. Isn't it a problem? Does Qualcomm pdQ allows to switch off transmitter/reciever while running a PDA? Will flight personnel understand that you are NOT using a phone? Is pdQ worth of its money if you cannot use it in flight? It seems that buying a PDA and a cellphone separately will be simply cheaper.

Re:And what about airplanes?

[lonely]

Indeed the phone will poll at full power looking for a base station when on the plane.

Another thought is what if you are going overseas and you are unfortuante not to own the GSM and going to America? You might still need the palm bit but the phone battery will flatten quickly......

It will be constantly screaming "Where is the base station, where is the base station" at full transmition power which can be a real drain. (Try taking any phone out of the coverage area)

Also in some countries it might be illegal to use the frequencies.. interferance with police cars and hospital equipment abound.

Keep them seperate I think!

Might not be a good purchase...

[tgd]

Anyone who hasn't owned a Qualcomm phone ought to think twice about buying one of these because they may not know what they're getting into.

In a nutshell, Qualcomm phones are pieces of crap. The original one that Bell Atlantic started selling when they first started adding digital service in CT was a nice enough phone, althoguh heavy. The flip up earpiece got loose fairly easily and the phone would randomly drop calls as a result.

Replaced that with a Q-phone when I switched to Sprint. Three months later the case was cracked and the antenna mount was broken. They replaced it as all of them had been recalled for that problem. Replacement phone had the same problem. I taped it up and dealt with it for almost nine months. Got sick of it, and replaced it again. Sprint gave me a hassle about it because the warranty on the original phone had expired, even though the second one wasn't a year old. I pointed out that they'd already admitted it was a problem with the phone and the "solution" of taking away my belt clip hadn't prevented it from breaking again.

So they finally gave me another one. That one didn't want to talk to their network. Reprogrammed it twice at the prompting of their tech support. No luck. Bring it back the next day, and get another one. Make a test call. That one works. (yay!)

That night, discover the voicemail and info buttons don't work. Neither does the * or #. Jump around an curse a lot.

Return phone, and tell them generally where they can stick their Qualcomm phones. Buy Startac. Talk for three times longer. Charge the phone almost ten times less often. Rejoice in a phone noticable lighter.

I can't imagine the pdQ is much better...

PCS and CDMA

[dublin]

t is worth noting that they do make a CDMA version, so you're not limited to PCS.

Sorry, but you seem a bit confused here. PCS (Personal Communications Service) is a generic name for the "new" 1900 MHz band authorized by the FCC for (what else?) digital personal communications services.

Within the PCS band, there are two common modulation methods, TDMA and CDMA. Qualcomm invented CDMA and only makes CDMA phones. All other CDMA phone manufacturers (Sony, Denso, Motorola, Nokia, Samsung) license the technology from Qualcomm.

TDMA (Time Division Multiple Access), allocates each user small time slice during which their phone may operate at full power to send intermittent blips of data. Note that although this can provide low-power usage (long battery life), it is not a low-power transmission.

CDMA is completely different and lets all users talk at once by relying on a "Pseudo-Noise" (PN) sequence mixed with the digital data stream to allow the reciever to separate it out, much like we can easily separate out a particular conversation in a crowded room. The PN codes within a cell are a set of "gold codes" designed to ensure that they are all orthogonal to one another - there's some cool and hairy math in there. CDMA does not use time slices, but rather transmits as needed while dynamically adjusting power to the lowest practicable level to avoid stepping on other signals. (It is this "power-agile" nature of CDMA that proved to be the hardest engineering problem, and delayed its deployment by several years.)

CDMA has several distinct advantages over TDMA: It has been shown to offer the highest bandwidth usage of any system (this was true a few years ago, I don't know if it's still true with the new pulse position/wavelet systems or not), and most importantly for mobile digital data, it offers "Soft Handoff". This is a slick byproduct of the way CDMA works: since only your code differentiates your signal, not the frequency, it's possible to be in contact with two (or even more) cell stations simultaneously, and the network has the ability to dynamically choose the best signal. This provides very smooth handoffs since there is not a single "cutover" point at which you are talking only to the "new" cell, even though a moment later, you may again have the best connectivity through the "old" one. For voice, this doesn't much matter, because we have these really cool giga-neuron analog signal processors between our ears to plug the gaps, but it's very important for data streams, where there are just finicky computers listening.

CDMA's excellent support for mobile data connectivity is the reason I and many ohters believe that CDMA must ulitmately triumph, and why Qualcomm's stock went through the roof last year, to the point that it now has a P/E of 300 - unheard of for a comms company (Cisco's is only a little over 100!)

(Incidentally, the very sharp rise-time/fall-time edges of TDMA (and GSM, which uses TDMA modulation at a different frequency and much higher power) are suspected to have a far greater impact on biological systems than the pseudo-noise signal of CDMA. Most of the studies showing a linkage between cellphone usage and biological effects involve TDMA or GSM phones. This also may ultimately have an impact on CDMA's success, especially the next-generation broadband CDMA systems.)

I suppose I sound like a cheerleader here, but CDMA *is* cool technology.