Status Byte Register - Agilent Technologies E4406A VSA Series Programmer's Manual

Programming Fundamentals
Using the Instrument Status Registers

Status Byte Register

The RQS bit is read and reset by a serial poll. MSS (the same bit
position) is read, non-destructively by the *STB? command. If you serial
poll bit 6 it is read as RQS, but if you send *STB it reads bit 6 as MSS.
For more information refer to IEEE 488.2 standards, section 11.
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