3G is a radio technology used for both voice and data. In other words, 3G is NOT just about the Internet. In fact, phone calls are also placed over 3G and usually there is better call quality and reliability over 3G. (Quality obviously varies based on the cell towers in the area). The 3G toggle in the Android settings of GSM phones will cause the phone to fall back to 2G for both voice and data.

Many users confuse “3G” with mobile Internet. They think disabling 3G prevents their phone from using the Internet. For users looking to disable mobile Internet on their phones, please search for “APNDroid” on the Android Market which offers a plug-in for Locale.

There is also another plug-in called the “Locale Mobile Data Plugin” which contains a condition for detecting Internet usage as well as a setting for disabling mobile Internet over the cell network.

While Android claims that switching from 3G to 2G will save battery power, this is not a huge savings. While actively browsing the Internet, 3G will likely require less power because it is faster and it will take less time to find something.

For users really wishing to slow down their Internet connection by switching the 2G/3G setting on GSM phones, there is also the Toggle 2G app with a Locale plug-in on the Android Market which requires the Cyanogen ROM in order to work properly. Note that toggling 2G/3G in such a manner will disrupt the phone entirely (voice and data) for about 30 seconds during the switchover. For users running stock versions of Android, this plug-in will not work and it is absolutely impossible to toggle the 2G/3G setting.

The original request here was for a logical NOT operator, although it doesn’t make sense to create a logical NOT operator in Locale. Most of the time, NOT isn’t the right way of thinking about a Condition. For example, NOT 9 am to 5 pm could be redefined as 5pm to 9am. NOT at work would simply be the Default situation. For the other conditions built-in to Locale, thinking about the problem in a different way usually means that NOT isn’t needed. If a Condition truly needs NOT logic, then that should probably be put into the individual Condition’s UI itself rather than as part of the Edit Situation screen in Locale.

Although this request is for a NOT operator, I believe the underlying request here is a way of detecting the transition between situations. The strongest use case would be detecting when you’ve left a particular Location. While Locale can easily detect the transition between situations, providing a UI to allow the user to do something with that transition is extremely complex.

Today, Locale treats situations as a continuous event. When Locale determines that a situation is active, it applies that situation’s settings. When leaving a situation, a lower priority situation’s settings take precedence (usually the Defaults). This provides a single, consistent behavior that makes Locale easy to understand.

One suggested implementation is to have “On Enter” and “On Exit” settings within a situation. On Enter settings would work like the current settings within Locale, while On Exit would be applied when leaving a situation. But what if the On Exit settings of a situation are in conflict with the On Enter settings of a higher-priority situation? The number of arrangements that the user must think about has just doubled.

We’re still evaluating ways to solve the underlying requeste of “leaving a location”, without making the UI too complicated…