Testing of mobile phone designs before they enter service and are used on a live network is particularly important. Users expect their phones to operate correctly to be able to make calls, and for all the features to work as intended under all conditions. The huge variety of phones on the market means that a user can easily change to another manufacturer, and in a market that is very sensitive a manufacturer can soon get a poor name. With the vast number of phones of any given design being produced, recalling them is not normally a viable option. Additionally, it has been known for incorrectly operating phones to cause problems to the network operator.

Ensuring that phones operate virtually perfectly is not an easy task. The specifications used to define the standard are usually very extensive, and can be open to interpretation in some places. Essential operations such as registration require many transactions between the phone and the network, and as a call proceeds the network and phone have to keep in communication with one another to ensure that the call is maintained. Handover and other scenarios then introduce further complications. All these interactions must proceed correctly, despite the huge number of communications that are undertaken under a wide variety of scenarios. With the introduction of 3G these protocol exchanges have become increasingly complicated, and still demand the same high level of operation. In addition to this, many physical elements of the phone need to be tested ...