EXFO FLS-5800 CD/PMD Analyzer Source - Manual (Page 38)

Controlling the Source Remotely
32 FLS-5834A
Standard Status Data Structure
An SRQ is forced when a bit in the status byte register goes from 0 to 1 and
the corresponding SRE mask bit is set. If an SRQ is forced, the RQS bit is set
to 1 and will remain there until read by a serial poll –even if the reason or
condition causing the service request no longer exists. Similarly, if a serial
poll reads the RQS, it is reset to 0, whether or not the condition causing the
service request still exists.