Dataman S4 - Manual (Page 25)

DATAMAN S4 MANUAL
LIB KEY 25
another 42 byte, followed by another START
and END, and so on. When the LIBRARY
program has been loaded, S4 resets and runs
it.
At the end of the table of blocks there is a byte
which is not 42. If this byte is 00, 54 then S4
picks up the following two bytes as a start
address and executes it. If it is not 00,54 then
S4 returns to the command prompt.