[General Topics] Menneisyys:
Now that I’ve become a proud owner of a super-mobile HP TC1100 Tablet PC, using mobile devices (smart phones) as external modems have became essential for me. Up until now, I’ve done most of my Web browsing, YouTube watching outdoors with some of my mobile devices. Having multiple mobile Internet access subscriptions, at times, I’ve used several of them at the same time – for example, watching a YouTube clip on my Nokia N95 while checking my mail on my BlackBerry; therefore, modem usage wasn’t that important for me. Now, the situation has completely changed: I take my HP almost everywhere, thanks to its (and the computer case’s) low weight and, of course, need (cellular and, preferably as fast as possible, that is, HSDPA) Internet connection everywhere. This was the most important driver for my scrutinizing all the possible solutions and comparing them battery life-wise to know how I can maximize battery life. Another driver was the brand new Internet / Connection Sharing category I’ve created in the Smartphone & Pocket PC magazine Best Software Awards 2008: with brand new titles / categories out there, I prefer to give my readers a very thorough review of them so that they see what the new categories are all about and why I've created them in the first place. Finally, I wanted to publish a greatly updated sequel to my previous, related articles and tutorials (see the Appendix for links).

This Bible is multiplatform, as with many of my recent, other tutorials and roundups: in addition to Windows Mobile, I also discuss Symbian s60v3 and BlackBerry. Please don’t come telling me "Why one Bible for all these operating systems and why don’t you break this into three separate articles?" The answer is manageability: with three separate articles, I’d need a lot more time managing, updating, quickly editing, changing them in the future. Also, the stuff I discuss has cross-references; for example, in the Symbian s60v3 and BlackBerry sections, I refer back to the Windows Mobile section. Separating this info, also meaning reusing the same sections, into separate articles would have been a pretty complicated task. Finally, if you have smart phones you’d like to utilize as modems with not only one operating system, you’ll certainly welcome having all the information in one place, not needing to find my other, related articles. Just skip the sections not discussing your particular operating system if you disagree with my approach.

(Incidentally, now that even Smartphone & Pocket PC magazine announced they would start covering the iPhone with a dedicated paper(!)mag, you may ask when I start doing the same. First, I'm European and, as you may already know, it's far harder for us to get an officially (!!) unlocked phone here. It's only now that Finland, at last, has become one of the countries where iPhones are sold that I can buy such a phone without having to travel to another country. Too bad it seems it won't be unlocked, which is plain unacceptable for me. That is, I may need to rely on factory-unlocked phones imported from Italy. And it still isn't known how much they would cost. Just a comparison: in Finland, the locked TeliaSonera 8GB model costs 477€, including the 24*1,99€ of the cheapest 24-month Minun Sonera contract. In Italy, the unlocked iPhone costs about the same - but that's in Italy. I wouldn't buy a locked iPhone because, however much unlocking works just great now, it's in no way guaranteed this will be true of future firmware revisions. All in all, I'm still not sure whether I am able to purchase the iPhone 3G or not.)

As you’ll see, using current smart phones may prove better, power consumption-wise on the notebook side, than the currently used USB or PCMCIA modems – or the built-in WAN support (HSDPA modem) in some higher-end notebooks and UMPC’s like the Lenovo Thinkpad X300. If you use an external smartphone not taking any charge from the USB port like a Nokia N95 tethered to your notebook, you can increase your notebook’s battery life by 5…40% (depending on the notebook used, the CPU load etc.) because, in general, the power usage difference can be as high as two Watts. I very thoroughly discuss these questions as well in the notebook power consumption-related sections.

1.1 Setting up the connection

In here, I explain how you can set up the connection from Windows-based desktop (notebook etc.) computers. On non-Windows client machines, the situation is pretty much the same if you plan to connect to Bluetooth (BT) Dial-Up Networking (DUN) (or, with the now-rare Widcomm BT stack, BT Personal Area Network (PAN)) or Wi-Fi connections; consequently, I don’t spend much time on it. I can, however, publish a Vista update if I receive a lot of feedback asking me to do so.

In the next three main sections, I explain the three ways (USB cable, Bluetooth DUN / PAN and Wi-Fi) you can tether your smart phone to your desktop PC – or, of course, other smart phones, PDA’s or wireless-enabled gaming consoles. I don’t discuss infrared connections (IrDA) because very few current Windows Mobile smart phones support them any more. On Symbian and BlackBerry, where IrDA is still very common, you still don’t really want to use them because of the slow speed. (Very few – if at all – smart phones use Fast Infrared [FIR]; the rest only operate at 112 kbps at most. Even Bluetooth is much faster, let alone cabled (USB) and Wi-Fi connections.)

1.1.1 USB

In the first subsection, I explain the most power-saving approach: tethering smart phones acting as modems (from now on, "modems") to your notebook. (From now on, I refer to the client as a "notebook". Please note that it can be anything: a desktop PC needing cellular Internet connectivity; a UMPC or even a non-Windows-based mobile device. For example, I’ve successfully used Symbian smart phones using a Windows Mobile modem - and vice versa. That is, it, the client, doesn’t even need to have a desktop operating system to be able to use the Internet connection of the modem. I even provide compatibility info in the main charts below on using smart phone clients.)

As USB connectivity requires no wireless connections (Bluetooth or Wi-Fi) between the modem and your notebook, in cases, it can be the most power-efficient solution on both the notebook and the modem side. Using Bluetooth decreases battery life by, in general, some 2...20% on both the notebook and the smart phone side. Using Wi-Fi can have an even more dramatic impact on the battery life, particularly those of some Symbian smart phones like the Nokia N95, where the battery life can be reduced by 50…70% if you opt for going for Wi-Fi.

Note that as it’s only desktop operating systems (Linux, Windows, Mac OS X) that have USB drivers and very-very few mobile devices (like the HTC x7500 / x7510 Advantage and the HP iPAQ 21x) have hardware USB host functionality, you can’t use USB tethering (cabling) between other smart phones or gaming consoles and modems. Also note that tethering has another major problem: the cable itself, which, in cases, can really hamper the usability, mobility etc. of the notebook, particularly with truly handheld UMPC’s and small Tablet PC’s often rotated between portrait and landscape orientation in "slate" (no-keyboard) mode. For example, look at the TC1100-in-use shots in my last Misc news article showing an external USB HSDPA modem. The shots certainly show how awkward it is to use USB cabling in a Tablet PC, particularly if you plan to walk around with them (the typical healthcare Tablet PC usage) and/or plan to rotate it while keeping it in your hand. Now, think of walking around with a cable or, even worse, a USB modem on a short cable sticking out from the tablet PC, swinging all the way around and/or getting caught by obstacles like doorhandles.

In the latter cases, you will want to prefer a wireless tethering solution (Bluetooth or Wi-Fi) between your modem and notebook.

1.1.1.1 Windows Mobile

As with the case of Bluetooth, there’s a huge difference between how old(er) and new(er) Windows Mobile modems behave. The former constitute all modems running an operating system before WM5 AKU3. (This major OS uprade was released in Autumn 2006; see THIS for more info on its networking if interested. Note that the article is pretty technical and is not required for the understanding of the current Bible.)

WM5 AKU3 has completely (!) changed the way Windows Mobile modems act: Internet Sharing has been introduced and the old approach entirely abandoned. It’s entirely different, both when used over USB and Bluetooth.

Note that some unofficial, "cooked" WM 6+ ROM’s (for example, the latest, 7.7 version of Tomal’s HTC Universal ROM) support both approaches – that is, not only the newer Internet Sharing-based one, but also the older, standard approach. It's also possible to "hack" the "old" approach to some (not all!), current devices - see THIS for more info.