AT Commands Reference Manual - wireless netcontrol GmbH

Chapter 3: AT Commands Reference
&C, Circuit 109 Behavior
This parameter determines how the state of the DCD line relates to the detection of the received
line signal from the distant end. Changing the parameters will take effect immediately in both the
command and online command states.
The DCD line is an output line that indicates the following:
• In Circuit Switch Data mode an active (low) indicates that a valid carrier (data signal) was
detected by the H24 (CONNECT message is received), and inactive (high) indicates idle.
The AT&C command always puts the DCD command ON, when set to 0. If the AT&C
command is set to 1 then the "+++" escape command sets the DCD signal to an inactive state
and the ATO command is set to active. The AT&C set to 2 sets the DCD signal OFF.
• In GPRS mode, the DCD line indicates the PDP context status. PDP context active sets the
DCD to active (low); PDP context inactive sets the DCD to inactive (high). The DCD is
activated only when the PDP context is achieved. The DCD is de-activated when the PDP
context is off.
• In Local Link mode, the DCD line indicates the Local Link data status.
When AT&C is set to 0, the DCD signal is always ON.
When AT&C is set to 1:
• DCD signal is set to ON when +MDLC command has been launched.
• DCD signal is set to OFF when Local link has been stopped.
When AT&C is set to 2, the DCD signal is always OFF.
When AT&C is set to 0, the DCD signal is always ON. When AT&C is set to 1, the DCD is
activated in online mode. When AT&C is set to 2, the DCD is activated only when the PDP
context is achieved (temporary IP address is received).
Command Type Syntax Response/Action
Set AT&C OK
Read AT&C? &C:
Test AT&C=? &C:(list of supported s)
April 15, 2010 H24 - AT Commands Reference Manual 3-161