Q: My daughter and I both have iPhone 4S smartphones. We recently had all of our contact lists deleted for no apparent reason, and it seems that I have no way to retrieve them. What happened, and what can I do?

Cindy Atsatt, Minneapolis

A: Why this happens isn't clear, but the same problem has been reported by many people using an iPhone with the operating system iOS 5.1.1. There are several potential solutions, one of which may work for you.

The most obvious one is to reload your contacts from a previous backup, if you made one.

To recover your contact list from a previous backup copy in iTunes, go to tinyurl.com/ndam3mj and scroll down to "How to recover your iPhone contacts." Note that this method has an unfortunate side effect: It will erase songs and videos stored on your phone. So copy those iPhone files to your computer before restoring your contacts.

To recover your contact list from a previous backup copy on iCloud, Apple's online backup site, go here.

Alternatively, if you originally copied your iPhone contact list from Microsoft Outlook, the e-mail program, you could copy it from there again. See here.

There are several other potential solutions that have been recommended by iPhone users since 2011, when an earlier version of the operating system, iOS 5, caused a similar problem. Look here for some.

The best way to prevent this from happening again is to regularly back up the entire contents of your iPhone to iTunes. See video on that here.

Last week's column about alternatives to having a wired telephone line prompted a couple of informative comments from readers.

Julie Ford of Manteca, Calif., noted that the price of giving up a wired telephone is that emergency calls aren't as automatic as before. That's because wireless 911 calls don't automatically deliver your home street address to the emergency operator as wired 911 calls do. You must tell the 911 operator exactly where you are. Cellular companies do provide the emergency operator with your approximate location, based on your phone's GPS chips (which use the Global Positioning System that relies on satellite signals) or by measuring your position in relation to nearby cellular towers. If this is a major concern for you, hang on to your land line.

Brian Hols of Minneapolis noted that I left out a major alternative for people in Minneapolis who want to drop their phone lines: the Minneapolis Wi-Fi network. USI Wireless, which manages the city network, offers a tier of service with download speeds of up to 6 megabits per second, fast enough to watch streaming video without problems.

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