Automatic Call Clear Sequence; Call Clear Sequence From Land - Furuno IB-681 Operator's Manual

3.4.4 Automatic call clear sequence

An automatic call is cleared when the DTR signal is received from the HSD terminal.
The HSD terminal turns off DTR, then the automatic call is cleared.
The HSD terminal sends clear signal to CES, then HSD modem turns off DCD and
CTS. Finally HSD modem turns off DSR.
CES
HSUB
Disconnect
Ch. release SU

3.4.5 Call clear sequence from land

Land clears automatic call, then CES sends clear signal. The HSD modem turns off DCD
and CTS. Finally, the HSD modem turns off DSR, and the HSD terminal turns off DTR.
CES
Disconnect
from land
Max. 2 min
Ch. release SU
delay
HSUB
Ch. release SU
NCS
CESI
Figure 8 Automatic call clear sequence
NCS
CESI
Figure 9 Call clear sequence from land
15
FELCOM
Ch. release SU
10 times
FELCOM
HSUB
Ch. release SU
10 times
DTR OFF
DCD CTS OFF
DSR OFF
DCD CTS OFF
DSR OFF
DTR OFF