[JohnBHanson]

Early keyboards were arranged so that shift changed the ASCII output from numbers (0x30-x3f) to (0x20-0x2f) and letters from (0x60-0x7f) to (0x40-0x5f). This is simple logic
to change bit 5/4 when the shift key is pressed thus saving space in the decode matrix.

This keyboard looks to be that type. It should be noted that although the matrix in a teletype keyboard was slots in metal the same trick was used to change (0x30-0x3f) to (0x20-0x2f) for the shift key (teletypes did not support upper case.

Latter keyboards had shifted9=( etc