The HEADers? query returns all SCPI commands and queries and IEEE 488.2
common commands and common queries implemented by the instrument. The
response is a <DEFINITE LENGTH ARBITRARY BLOCK RESPONSE DATA> element.
The full path for every command and query is returned separated by linefeeds. The
syntax of the response is defined as: The <nonzero digit> and sequence of <digit>
follow the rules in IEEE 488.2, Section 8.7.9. An <SCPI header> is defined as: It
contains all the nodes from the root. The <SCPI program mnemonic> contains the
node in standard SCPI format. The short form uses uppercase characters while the
additional characters for the long form are in lowercase characters. Default nodes
are surrounded by square brackets ([]).