PCB Identifiers beyond 9U

Explanation

If a fixture has 10 or more uploadable PCBs, letters are used in place of numbers above 9U for the software identifiers printed on the PCBs.

For example, Lonestar Prime uses 10 software packets: 1U–10U. The PCBs are labeled with these identifiers (see the first picture below).

Two-digit numbers will not fit in the label space, so the 10U PCB  will be  AU (see the second picture below).

AU=10U,  BU= 11U, CU= 12U, and so on.