In a typical IFF/SIF system, how many codes can be selected in Mode 2?

In a typical IFF/SIF (Identification Friend or Foe / Selective Identification Feature) system, Mode 2 is specifically designed to provide a unique identification code for friendly aircraft. This mode allows for a total of 4096 different codes to be selected.

The structure of the IFF/SIF codes in Mode 2 is based on a binary system, and since there are 12 bits available for the code, the calculation for the total number of possible combinations is 2^12. This results in 4096 unique codes (from 0 to 4095) that can differentiate between various friendly units.

The availability of these codes is crucial for ensuring that the system can meet operational requirements, particularly in combat situations where proper identification is essential to prevent friendly fire incidents. The design of Mode 2 allows for a sufficient range of codes to be assigned to different units while maintaining clarity in identification.