Embarrassed Apple admits iPhone exaggerates signal

All 50 million iPhones overestimate the strength of their signal, the US computer giant Apple admitted yesterday.

Owners of the bestselling smartphones have long complained that they experience calls that fail to connect or break up mid-conversation when the phone indicates an adequate signal.

The problems have increased with the latest incarnation, the iPhone 4, with users reporting a loss of signal if they grip the device over the antenna.

Last night Apple emailed iPhone 4 customers to explain that a software fault exaggerated the strength of the signal, indicating that calls could be made when they could not.

The company will release a software patch to repair the fault on the iPhone 4, as well as on earlier models the 3G and 3GS, in the next few weeks. Owners of the iPhone 4, which is sold out, will be offered refunds if they are unhappy after the update.

Apple said the software problem had been present from the first iPhone, sold three years ago. The iPhone illuminates up to five bars to indicate signal strength.

Apple admitted the devices overestimated the strength by up to two bars. "We have discovered the cause of this dramatic drop in bars, and it is both simple and surprising," the company wrote to customers.

"We were stunned to find that the formula we use to calculate how many bars of signal strength to display is totally wrong. Our formula, in many instances, mistakenly displays two more bars than it should for a given signal strength. For example, we sometimes display four bars when we should be displaying as few as two bars."

It continued: "Users observing a drop of several bars when they grip their iPhone in a certain way are most likely in an area with very weak signal strength, but they don't know it because we are erroneously displaying four or five bars. Their big drop in bars is because their high bars were never real in the first place."

- THE INDEPENDENT