2 receiving, 1 automatic call mode and receiving operation, Address call and dtr on – Furuno IB-681 User Manual
Page 19: Address call and dtr off
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3.2 Receiving
Certain HSD terminals cannot receive the RI signal and therefore cannot receive.
3.2.1 Automatic call mode and receiving operation
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Address call and DTR ON
When a call arrives, the HSD modem turns RI ON and then acknowledges reception by
sending INC to the HSD terminal. (See page 10.) Five seconds after sending INC receiv-
ing processing is initiated. When processing is completed, RI goes OFF and DSR, CTS,
DCD go ON to communicate over land line.
If the HSD terminal sends the DIC command to the HSD modem, the HSD modem does
not initiate receiving processing. This happens in the following instances:
• Overlapping calls (receiving processing cancelled)
• Processing initiated within five seconds after INC is received
If this occurs while the call is being relayed, the CIC command is sent and the HSD mo-
dem reinitiates processing.
Address call and DTR OFF
When a call arrives, the HSD modem turns RI ON. This tells the HSD terminal to turn on
the DTR signal, which causes the HSD modem to send the INC (indication) signal to the
HSD terminal to indicate it is receiving. The HSD terminal then sends the CIC command to
the HSD modem which initiates receiving processing. When processing is completed, RI
goes OFF and DSR, CTS, DCD go ON to communicate over land line.
When DIC is sent by the HSD terminal instead of CIC, the HSD modem sends the indica-
tion VAL. In this case processing is not started. Furthermore, when the CRN command or
other three-character command is sent the HSD modem sends the indication INV.