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.

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Furuno IB-681 manual V.25bis Command, Indication, Receiving and automatic data rate switching, SW3 State Remarks