If you have an iPhone, this experience may be familiar: Your phone shows only a bar or two, and either you can't make a call or the call you do make is so scratchy and garbled that the person you're calling can't understand what you're saying. Meanwhile, right next to you, someone on a different AT&T phone connects without a hitch and chats away happily. I decided to informally test whether there's a solid basis for that common gripe. My findings: The two iPhones I tested had lower rates of connecting successfully and had poorer voice quality in AT&T low-signal areas than did two non-Apple AT&T phones that I tested under the same conditions.
I tested four phones on AT&T service in two cities over three days. I drove around San Francisco and Los Angeles comparing the performance of the iPhone 4 and the iPhone 3G S against the performance of the RIM BlackBerry Bold 9000 and the Pantech Impact in voice calls placed at roughly the same time from areas where coverage from the AT&T network is less than optimal.
[ Looking for more smartphone comparisons? Check out InfoWorld Test Center's "Mobile Deathmatch: RIM BlackBerry Torch 9800 vs. Apple iPhone 4." | iPhone, BlackBerry, or Android? Whatever handheld you use or manage, turn to InfoWorld for the latest developments. Subscribe to InfoWorld's Mobilize newsletter today. ]
What I found was surprising. Calls on the iPhone 4 and iPhone 3G S failed to connect or dropped in midcall far more often than did calls on the other two phones, and the iPhone calls that connected successfully sounded marginally worse than calls placed with the BlackBerry and Pantech phones.
My testing is not meant to be scientific or definitive, but the results raise real questions about the world's favorite smartphone: Is the iPhone a great personal computing device but a bad phone? Please click the chart below to see average call quality scores (on a 1-5 scale) for all test calls made in San Francisco and Los Angeles.
I made test calls from seven medium- to low-signal locations in San Francisco; then I validated my results with a second round of testing at the same locations two days later. Finally, I performed similar tests from five locations in Los Angeles. I tested from various locations, including a parking garage, a forest, a train station, a library basement, and a moving bus. I noted each dropped or failed call, and scored each successful call that I made using the five-point Mean Opinion Score (MOS), a scale developed by Bell Labs to quantify call quality. (Please see the "Mean Opinion Scoring Guide" -- the rightmost column in the chart above-- for definitions of the possible call quality scores, 1 through 5.)