The “Reset Network Settings” button on the iPhone not only resets your Wi-Fi settings — resulting in a clean slate with respect to Wi-Fi access points and their passwords — it also resets your phone carrier settings. Several months back, I had the darndest trouble with cellular data access. I could place and receive calls, but couldn’t get cellular data access no matter what I did. I tried going into and out of airplane mode, turning the phone on and off, and resetting it, all with no luck.

So I decided to call AT&T. Apparently, one of the cell phone towers near my office was having trouble and fell out of and back into commission. And although the tower was back up and running, my iPhone was stuck in cellular data purgatory. AT&T support suggested that resetting the network settings on the device would likely resolve the issue: and it did. Resetting network settings has also helped me resolve an issue I was having with Visual Voicemail, (see footnote below), on another occasion.

To reset your iPhone’s network settings, tap your way to Settings > General > Reset > Reset Network Settings. With great power also comes great annoyances, like having to reconnect to previously remembered access points and having to re-enter passwords.

Footnotes:

Visual Voicemail

This happened to me last time I upgraded from my original iPhone to the 3G. I went to check messages, and instead of seeing the list of people who called, the phone simply dialed the voicemail number. The solution this time is the same as last time.

Go to the AT&T web site, log in, and under Phone, Device Support you’ll see an option to ‘Reset Voicemail Password.’ Go ahead and do that, and AT&T will send you a text message with a temporary password. Go to your iPhone, set up Visual Voicemail again as if your phone was new, and put your old password back in.

It seems like AT&T could handle all this automatically, and it clearly works for some, but a quick check of friends who upgraded found quite a few with the problem. All this logging in and re-setting passwords is not the most elegant solution, but apparently it is the only solution.

Hope this helps some of you