Furuno IB-681 manual V.25bis Command, Indication, Receiving and automatic data rate switching

3.2.2 Receiving and automatic data rate switching

A call arrives at the data rate set on a subscriber’s equipment, and the setting of DIP Switch SW3 determines if the call will be received or not when the data rate is different from that set on the IB-681.

SW3 State	Remarks
	HSD call not accepted when its data rate is different from that
OFF: No automatic	set on the IB-681.
data rate switching	Use this setting when the synchro clock to the HSD terminal
	cannot automatically be changed to match data rate.
	HSD call accepted regardless of data rate. For example, if the
	Rate switch is set to 64 K and a call's rate is 56 K, the call is
ON: Automatic data	transmitted at 56 K. The synchro clock signal to the HSD
	terminal is also automatically changed to 56 K.
rate switching
	Note: The HSD terminal is required to automatically synchronize
	to varied clock signal.

3.3 V.25bis Command, Indication

For automatic calling, the HSD terminal directs the HSD modem with commands. Addi- tionally the HSD modem directs the HSD terminal with indications. These commands and indications are as below.

Commands

Command	Name	Description
CRNxx ⋅ ⋅ x	Call Request Number	Transmit a call
DIC	Disable Incoming Call	Prevents automatic reply.
CIC	Connect Incoming Call	Allows automatic reply.

Consecutive commands cannot be accepted. Commands use IA5 characters. Upper case or lower case may be input, but case cannot be mixed.

Indications

Indication	Name	Description
INC	Incoming Call	Call has arrived.
INV	Invalid	Error in command from terminal.
VAL	Valid	Accept command from terminal.
CFIxx	Call Failed	"Call failed reply" (and reason) in response to CRN

Indications are done with IA5 characters, in upper case only.

10