This issue affects iOS7 and above and users of TTerm 1.1.0 or above. For keyboard limitations in iOS6 devices see here

In TTerm 1.1.0 and above key mapping allows emulation Function (Fx) and Programmable Function (Pfx) keys to be mapped elsewhere, typically emulation F1 to F10 is mapped to Command + 1 through Command + 0 on your bluetooth keyboard and F11 and above is mapped to Command + Q (directly below the 1 key) and so on.

Due to restrictions in iOS concerning which keys TTerm can directly access, physical function keys are not supported on bluetooth keyboards.

The key mapping function in TTerm can be found be tapping Edit configuration > keyboard > bluetooth keyboard. Here you will be able to list the emulation keyboard function keys and their bluetooth key equivalents. If these defaults mappings are not to your liking they may be altered.

Listings of the default keyboard mappings for each individual emulation are provided elsewhere in this FAQ.