EXFO FTB-7000 OTDR Series for FTB-500 - Manual (Page 350)

SCPI Command Reference
336 OTDR
Product-Specific Commands—Description
:CALCulate[1..n]:IORefraction?
Description This query returns the index of refraction used
for the trace corresponding to the specified trace
index.
Since *RST clears the index of refraction value,
the returned value will be 0.
Syntax :CALCulate[1..n]:IORefraction?TRC1|TR
C2|TRC3|TRC4
Parameter(s) Label:
The program data syntax for the first parameter is
defined as a
element. The allowed
DATA> elements for this parameter are:
TRC1|TRC2|TRC3|TRC4.
Trace index of the available wavelengths.
Response Syntax