You should know by now that an iPhone of the right vintage can be turned into a mobile hotspot—a portable router that pumps out a Wi-Fi signal on one side and talks to a mobile 3G broadband network on the other. We’ve covered the Personal Hotspot feature for both the Verizon iPhone 4 and for the the GSM-based iPhone 4 used by AT&T in the U.S. and other carriers around the globe.
The Personal Hotspot feature also lets iPhones starting with iOS 4.2.6 (Verizon) or 4.3 (GSM model) share the cell data connection via Bluetooth and USB as well. All iPhone 4 flavors can allow up to three Bluetooth devices to connect as part of a total of five connections of any kind (among USB, Bluetooth, and Wi-Fi) at any given time. (The iPhone 3G or 3GS with 4.0 or later installed can accept one connection via Bluetooth.)
What you may not know is that the iOS 4.3 update adds Bluetooth tethering to every iPhone, iPod touch, and iPad capable of running that latest release. This lets any of those devices obtain an Internet connection from an iPhone with its sharing feature enabled. (Yes, you can even connect one iPhone as a client to another acting as a server in this manner.) It should also work with any computer, router, or mobile device that offers this kind of connection sharing over Bluetooth, such as Mac OS X’s Internet Sharing feature. Many other mobile devices can also tether over Bluetooth, as well as Mac OS X and Windows systems.
Why connect with Bluetooth
Bluetooth tethering has a set of advantages that might lead you to select it instead of Wi-Fi for routing your iOS device through an iPhone 4 Personal Hotspot. It also has a few drawbacks that might dissuade you.
For iPhone 3G and 3GS users, this form of tethering also allows other iOS devices to share a connection, which was previously impossible. (If either phone has iOS 4.0 to 4.2 installed, the sharing option appears as Internet Tethering. On an iPhone 3GS with iOS 4.3 installed, it’s labeled Personal Hotspot, though Wi-Fi isn’t available as an option.)
The key advantage of Bluetooth tethering is simplicity, especially with a streamlined pairing process for securely connecting two devices over Bluetooth that Apple added to the iOS with the 4.3 update. You can also likely save battery power on both the iPhone acting as a hotspot and the device or devices you to tether to it: Bluetooth should consume less power than Wi-Fi, even though modern Wi-Fi has a lot of built-in power-conserving features.
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