Specifications

SIM900 AT Commands Set
SIM900_ATC_V1.01 194 23.06.2010
OK
10.4 Call Control Commands
Demonstration Syntax Expect Result
Make a voice call ATD6241xxxx; OK
MS makes a voice call
Hang up a call AT H OK
Call dropped
Make a voice call using the last number
facility. The initial call is established
then cancelled. The second call is made
using the previous dial string.
ATD6241xxxx;
ATH
ATD L
OK
OK
OK
Example of a MT voice call Make MT voice call to
MS.
ATA
ATH
RING
RING
OK[accept call]
OK[hang up call]
Call related supplementary service:
AT+CHLD. This Command provides
support for call waiting functionality.
AT+CHLD=<N>
<N>=0 RELEASE
ALL HELD CALLS
OR SEND USER
BUSY STATUS TO
WAITING CALL
<N>=1 RELEASE
ALL ACTIVE CALLS
AND ACCEPT
OTHER
CALL(WAITING OR
HELD) <N>=1X
RELEASE CALL X
<N>=2 PLACE ALL
ACTIVE CALLS ON
HOLD AND ACCEPT
CALL <N>=2X
PLACE ALL CALLS
ON HOLD EXCEPT
CALL X
Return
value:(0,1,1x,2,2x,3,4,6,
6x,7x,8x,9x)
Terminate current call and accept waiting
call.
Establish a voice call from EVB, receive
an incoming call(incoming call accepts
waiting status), terminate active call and
accept incoming call. Note call waiting
must be active for this option – use
AT+CCWA=1,1
ATD6241xxxx;
<RX incoming call>
AT+CHLD=1
OK
OK
+CCWA: "62418148 ",
129,1,""
OK
<waiting call active>