In a serial poll, just as upon the command "*STB",
the status byte of an instrument is queried. However, the query is made
via interface messages and is thus clearly faster. The serial-poll method
has already been defined in IEEE 488.1 and used to be the only standard
possibility for different instruments to poll the status byte. The method
also works for instruments which do not adhere to SCPI or IEEE 488.2.
The quick-BASIC command for executing a serial poll is "IBRSP()".
The serial poll is mainly used to obtain a fast overview of the state
of several instruments connected to the GPIB bus.