in favor of AT&T’s older Edge network For the newer 3G-capable iPhones, turning off the 3G DVD Ripperin favor of AT&T’s older dvd ripper Edge network is sometimes effective. Go to the iPhone’s Settings icon. Tap General, then Network. Slide the Enable 3G toggle from On to Off. But you can’t talk and browse the Web at the same time on Edge.

Another alternative is to use a Wi-Fi hot spot to make calls. Skype, the popular Internet phone service, will make and take calls as long as you leave the app running and signed in. (Until an iPhone can multitask, that means you have to have the Skype app on all the time.) Calls with other Skype users are free, but calls to and from phones cost about two cents a minute. The app is available in the iPhone App Store.

Skype call quality varied in our tests from clear to sputtery, with a delay from one half-second to three or four seconds. Also, the app works only over Wi-Fi, so you will need to juggle between Skype and AT&T, depending on where you are.

Or, for $15 a month, you can subscribe to the Line2 app that mimics Apple’s phone in look and feeldvd ripper, but switches calls to a Wi-Fi network whenever the iPhone connects to one.

Line2 can start a call on AT&T’s 3G network and then transfer to Wi-Fi, whereas Apple won’t allow Skype to handle calls via AT&T. If left running, it will also receive inbound calls over Wi-Fi. (If Apple were to add a Wi-Fi option to the built-in Phone app, this wouldn’t be a problem.)

But for reliable service, there is no substitute for hardware that increases range. That is why AT&T has begun offering home 3G base stations that look like Wi-Fi routers, but send and receive 3G radio signals instead. These microcells, as AT&T calls them, connect to the Internet and offer wireless coverage of up to 40 feet in any direction. They work with any 3G AT&T phone, but not with Apple’s older non-3G model of iPhone.

The catch is that you will have to pay AT&T for the boost. There are two payment plans: If you buy the microcell for $150, AT&T will charge your voice calls made using the dvd ripper device against the minutes on your monthly wireless plan. OrDVD Ripper you can sign up for unlimited calling for a $20 a month fee, and get the microcell free.