With all the additional multimedia and work-saving functionality smartphones bring to the table, it's easy to lose track of the one basic requirement by which all handsets are ultimately judged: how well they keep that all-important voice link. It turns out that Apple and its iPhone 3G has that angle covered too: better than anyone.

Typically, one tends to blame the network or carrier for dropped calls, but the network's not always at fault. According to Nigel Wright, vice president of marketing for UK-based Spirent, a provider of wireless test solutions, up to 10 percent of dropped calls are due to deficiencies in the handset itself.

These issues can vary, from poor handling of hand-off between 2G and 3G networks, poor mobility capability and in the specific case of smartphones, poor firmware to handle push emails while on a voice call, causing the call to get dropped.

The iPhone 3G initially had a voice call problem when it debuted, but a quick-turn firmware upgrade from Apple solved the problem. "If you're focused on call quality, you can do quite a bit in firmware," said Wright.

It turns out that Apple did such a good job on that firmware upgrade that it came out on top of a number of popular handsets when it comes to call quality. Using equipment from Spirent, UK-based Broadband-Testing, an independent test lab, tested the ability of leading handsets to set up, maintain and handoff a call between networks. The handsets tested were the Apple iPhone 2.2 (3G), Blackberry Bold and Storm, Nokia E71, Samsung SGH F48, and Sony Ericsson (SE) c905.

In a prior test, performed by Signals Research Group, a phone from Icera came out on top, but Icera was not on Broadband-Tests list, so Apple came out on top, as shown below.

The handsets were tested under a host of circumstances and under a range of parameters, mostly to do with network-to-network handoffs, static vs. pedestrian vs. moving, and initial call setup performance. For the full report, click here.

According to Steve Broadhead, founder and director of Broadband-Testing and the man behind the report, there are a number of interesting insights to be gathered from the tests he performed. Primarily, it's clear that not all handsets are created equally and that even with the same vendor, chipset and/or firmware differences can have a large impact on call setup and maintenance quality. For more conclusions and further insights, including a full table of test parameters, see the full report.