AT Commands

Data Set Ready &S

These commands control the DSR signal generated by the modem to indicate that the modem is ready for operation. DSR must be on for some terminals and devices to communicate with the modem.

Command

Operation

 

 

&S

DSR always on

 

 

&S1

DSR on when off hook in data mode

 

 

&S2

DSR off for 5 seconds after disconnect then returns

 

to on

 

 

&S3

DSR follows off hook (OH) signal

 

 

Data Terminal Ready &D

In data mode DTR may be used for modem control.

Command

Operation

 

 

&D

The modem ignores DTR.

 

 

&D1

The modem goes to command mode from data

 

mode when DTR goes from on to off.

 

 

&D2

Disconnects when DTR goes from on to off;

 

disables autoanswer while DTR is off.

 

 

&D3

Disconnects, recalls command mode, and resets the

 

modem to a stored configuration when DTR goes

 

from on to off.

 

In dial line mode the modem disconnects; in leased

 

line, the modem retrains.

 

 

Note

If DTR controls dialer is selected, selecting DTR active will cause an autodial after an off-to-on transition of DTR.

5-20

Modem 3600

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Black Box 3600 MODEM manual Data Set Ready &S, Data Terminal Ready &D