The ASI-175-2 is capable of injecting simulated altitude frequencies into three altimeters simultaneously. The modulating frequencies {145,150, and 155 Hz} of the three altimeters can then be checked individually. The ASI-175-2 is also capable of simulating various rates of aircraft descent.

The ASI-175-2 receives the ARINC 429 altitude words from the altimeter under test and displays decoded altitude, along with the 429 word label and status. The Test Set can be set to read and decode either the binary or BCD 429 word from the altimeter. A functional self-test of the altimeter can be initiated at the test set. Built-in test equipment {BITE} results are displayed on the front panel annunciator.