EXFO FTB-500 - Manual (Page 355)

Data Types
FTB-500 347
Applicable Data Types for Output —IEEE 488.2

This data type is used by a device to return blocks of 8-bit binary
information when the block length was not predefined or when data
has to be computed later.
Note: If you receive a zero as the first digit (#0), it is necessarily followed by a
so that you will detect
the end of the DATA>.
Example: #0 where
“” stands for data byte.
# 0 <8-bit data
byte> TERMINATOR>