One of the biggest complaints about the iPhone 4 is its reception issues due to its unusual antenna design which takes the form of a metal band running round the edge of the phone. Although we could never replicate this issue ourselves and the iPhone 4S retains the same overall design, Apple has apparently added a new system which automatically switches between the new iPhone's two antennae for the best call quality. Apart from a slightly different placement of the silence switch, the only visual distinction between the iPhone 4S and its predecessors are that the small black 'breaks' in the antennae are in different places.
When tested in the IT Pro basement labs, a notorious cellular blackspot, our test callers reported to our surprise that the iPhone 4 sounded better than iPhone 4S.
When tested on a busy London road, our test callers were impressed by the clear, crisp, unimpeded sound quality of both the iPhone 4 and 4S. However, when tested in the IT Pro basement labs, a notorious cellular blackspot, our test callers reported to our surprise that the iPhone 4 sounded better than iPhone 4S. Although both suffered from a robotic, compressed sound and dropouts, those defects were more pronounced on the 4S. Both phones were tested on the O2 network.
One theoretical improvement the iPhone 4S has over its predecessor is support for 14.4Mbit/s 3G networks the older iPhone 4 only supports 7.2Mbit/s. This is unlikely to make much difference in practice though. As our sister title Computer Shopper discovered, you're lucky to achieve 1Mbit/s with any of the mobile networks.
Another potentially useful new feature is integrated support for CDMA mobile networks used in the US and a handful of other countries - the iPhone 4 was split into two different GSM and CDMA models. According to Apple, UK GSM iPhones should roam seamlessly onto a CDMA network, such as Verizon in the US, when travelling abroad. Only a simple tap of an onscreen control is needed to choose the cellular network in question.
