Codan NGT 2010 RF Technical & Service Manual page 788

8571—Technical description
If the ±10 mV tolerance is attained, the slave 8571 microprocessor instructs the master
8571 to report Optimal. However, if after the 20 attempts the tolerance limits are not
achieved, the microprocessor instructs the word Acceptable to be reported. If the latter
is reported, it means the line has been equalised and although it did not achieve the
optimum settings, performance should be satisfactory.
If the 300 Hz threshold fails to detect any 300 Hz tone after six attempts, the
microprocessor aborts the process and instructs the microprocessor in the master 8571 to
report Failed.
NGT Transceiver System Technical Service Manual 349