6.  Frequently Asked Questions 
 
6.1.  Question:  How can I tell which APS-3 model I have? 
  Answer: The APS-3 Serial number found on the bottom of the unit indicates 
the APS-3 model.  Serial numbers in the 10000 series are classified as APS-3. 
Serial numbers in the 20000 series are classified as APS-3 V2. 
 
6.2.  Question:  How do I calculate the slant height of the APS-3?   
Answer: Refer to the following diagram. Measure the slant height to the 
point as shown. The data collector software computes the vertical height 
from the measurements and dimensions, so manual calculation is not 
required with software that has programmed an APS-3 interface.