According to reports on the net, the problem regarding the iPhone 4S SIM card occurs regardless of the telephone operator and prevents users from activating their phones once the SIM card is in the slot.
Removing the SIM card and inserting it again seems to solve the problem, at least temporarily.
In the case of an iPhone at AT & T, the problem is even more serious because the SIM card is used to verify the user’s account and allow access to the device.
Some users say the problem appeared since the release of iOS 5.0.1. When this happens, basic functions such as making phone calls or sending text messages become unavailable, as the device is unable to connect with the wireless data provider.
In addition, numerous users have complained about problems emerging with the sound output of the device. The ear piece and the loudspeaker functionality of the device are the main concerns.
When users pressed the dedicated volume rocker keys, they said that the volume controller icon popped up but that the volume increase/decrease bars or the level indicator didn’t appear.
The iOS 5.0.1 update was released earlier this month in an effort to solve the battery life problems reported by some users.