iOS 4.1 Restores Field Test Mode

Gizmodo reports that iOS 4.1 has reincluded the Field Test mode to iOS. Field Test mode allows you to get a numerical figure for your antenna strength rather than the traditional bar measure. To get to Field Mode:

- First, upgrade your iPhone 4 -- or any iPhone -- to iOS 4.1.
- Dial *3001#12345#* into your phone [and press Call].

Pressing Home will exit you from the Field Test mode. For reference, Anandtech provides a good discussion about bar strength and signal values. Since that article was published, Apple has remapped the signal strength to # of bar ratio. More negative numbers are worse, and Anandtech reports they were surprised they were able to hold calls with signals as low as -113db.

Most customers won't care about their numerical signal strengths, but the antenna strength changes generated a lot of publicity surrounding the iPhone 4 launch due to issues with new antenna system.