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Lumia Field Test Mode


New member
Aug 14, 2013
While this is internal in the firmware, it's still a Lumia-specific application. Many Lumia handsets have an unlockable "Field Test Mode" (typically accessible by dialing ##3382#). I've personally used it on a Lumia 920, 1020, and a 635. The version of Field Test Mode (FTM) on all of these handsets appears to be indentical. I read that there may be a slightly different version for the variants of the 1520 that support FTM.

FTM is for geeky network analysis stuff, but it lets you do some potentially interesting things (like see what network frequency is being used by the handset), and some potentially useful things (like temporarily block out LTE for better battery life and a more reliable signal if you're in a strong HSPA area but handcuffed by a weak and unreliable LTE signal that your phone won't let go of).

The thing is, Lumia FTM appears to be entirely undocumented. Does anyone know of any online documentation for it? I've figured out through some research that I can translate the "EARFCN" field to know what frequency the phone is using, but it's inelegant. Any other documentation, or any tips and tricks from those who've used it in the past of things that aren't obvious?