AT Commands Reference Manual - wireless netcontrol GmbH

Chapter 3: AT Commands Reference
&D, Circuit 108 Behavior
This command determines how the H24 responds when the DTR (Data Terminal Ready) status is
changed from ON to OFF during the online data state. The DTR is an input line that indicates that
the terminal is ready.
The DTR line must be active (low) in order for the H24 to recognize the terminal. This signal is
raised by the terminal when a process activates the serial port. If the DTR is not used by the
application, it should connect this line to ground (DTR active). The default value is active (low).
In case of local link during initial PPP retries, DTR change will be ignored.
Command Type Syntax Response/Action
Set AT&D OK
Read AT&D? &D:
Test AT&D=? &D:(list of supported s)
The following table shows the &D parameters.
Table 3-99: &D Parameters
Description
The H24’s reaction when the DTR status is changed from ON to OFF.
In CSD calls:
0,4 Ignores DTR changes
1 Switches the CSD call to asynchronous command mode (the call remains
connected)
2,3 Disconnects the call and returns to the command mode
In GPRS calls:
0,4 Ignores DTR changes
1 Switches the GPRS session to asynchronous command mode (the session
remains connected)
2,3 Deactivates the GPRS and returns to command mode
In Local link:
0,3,4 Ignores DTR changes
1,2 Stop Local link. Return H24 to command mode.
The default value is 2.
Example
AT&D?
&D: 2
OK
AT&D1
OK
April 15, 2010 H24 - AT Commands Reference Manual 3-163