One of the new features included in iOS 4.3 for the iPhone 4/3GS is the Personal Hotspot. Other smartphones, such as those running the Android and webOS platforms, have supported this feature for a long time, so it's not a wholly new offering. It's simply available on the iPhone for the first time. Here's how it works.
Once the iPhone is done updating to iOS 4.3, Personal Hotspot can be enabled under the Settings > General > Network menu. It doesn't appear possible to enable the feature directly from the phone. I attempted to do so, and was redirected to ATT.com and instructed to call 611 from my phone.
I signed into my AT&T account online, and after several moments of searching, found the appropriate setting to alter. I switched from a $30 unlimited monthly data plan to the DataPro 4 GB with Tethering plan. This plan costs $45 per month, and is limited to just 4 GB of data. Thankfully, if you exceed 4 GB per month, AT&T charges a digestible overage of $10 per GB.
(Before I did this, I analyzed my data usage for the previous year. As it turns out, I've been less of a data hog than I thought. My average monthly data consumption has dwindled to just under 1 GB per month. Bottom line, I am not sorry to lose the "unlimited" data plan.)
Once I completed the changes to my account, I went back to the iPhone. The settings tools then allowed me to enable the Personal Hotspot feature from my device. The Personal Hotspot software assigns your device a network ID and password (to be used by other devices).
I turned on my iPad's Wi-Fi radio, found the iPhone, and connected. It was as simple as connecting to any other Wi-Fi network. The iPad was then able to access the Internet via the iPhone's cellular data connection to AT&T's network. (You can also choose to tether via USB.) The iPhone displays a bright blue banner at the top of the screen -- similar to what it does during phone calls -- to let you know that the Personal Hotspot feature is running.
I ran some tests.
First, I performed some general Web browsing. Web sites loaded quite fast. I also read some email, which also loaded quickly. I perused the App Store, and downloaded Ookla's Speed Test software to the iPad. The several speed tests I conducted showed the iPad was capable of averaging just over 1 Mbps on both the down and upload via 3G. That's not exactly blazing fast, but it is speedy enough for email and browsing. I wouldn't want to download an MP3 album or movie over those speeds.
I also called my iPhone from another line. As expected, it rang. I was able to conduct a voice call on my iPhone while it was serving as a personal hotspot.
Is this good enough to let you skip the laptop dongle or MiFi for mobile broadband? Well, the feature works as advertised and can certainly get the job done in a pinch. Personally, I'd prefer it if the speeds available were a lot faster (i.e., 21Mbps HSPA+ or LTE). For now, they are not.
If you can live with the somewhat slower broadband speeds, it works. If you want much faster Internet for your laptop and tablet devices, you might be better off waiting for a faster network technology to become available.