Keysight N1911A Programming Manual page 80

1 Power Meter Remote Operation
Status Registers
The Status System in the power meter is shown in
Status and Questionable Status groups are 16 bits wide, while the Status Byte and
Standard Event groups are 8 bits wide. In all 16-bit groups, the most significant bit
(bit 15) is not used and is always set to 0.
80 N1911A/1912A P-Series Power Meters Programming Guide
Figure 1-9. The Operation