Call Control
3-28 AT Commands Reference Manual June 30, 20 08
Example
AT+CH LD= ?
+CHLD: (0,1,1x,2,2x,3)
OK
AT+CCWA=1 //Enable call waiting
OK
atd9311234567; //Originate a voice call
OK
OK
(...conversation...)
+CCWA: "+358317654321",145,1,"Bob" //Awaiting call alerts
AT+CHLD=2 //Put first call on hold and answer the second call
OK
(...conversation...)
AT+CHLD=3 //Add the held call to the conversation
OK
(...MTPY conversation...)
AT+CHLD=22 //Split: Place the MO active call on hold, MT call remains active
OK
AT+CHLD=0 //Release the held call
OK
NO CARRIER
ath //Release the active call
NO CARRIER
OK
atd9311234567; //Originate a voice call
OK
Held (Single
or MTPY)
Call and
Waiting Call
Releases
waiting call. Accepts
waiting call. Error 3. Accepts
waiting call. Error 3. Error 3.
Single (or
MTPY)
Active Call
and Single (or
MTPY) Held
and Waiting
Call
Releases
waiting call. Releases
active call,
and accepts
waiting call.
Releases
specific
active call x.
If x does not
exist, then
error 22.
Error 3 (too
many calls on
hold.
Error 3. Makes a
conference
call. Waiting
call is not
touched.
Split: Places the active MTPY call on hold, except for a specific call x.
Switch: Places the active call on hold and accepts the Held call
Error 3: "Operation not allowed"
Error 22: "Not found"
Table 3-11:+CHLD Actions According to Call State and Operation (Cont.)
Call State
CHLD <operation>
0 -Release
Held Call
1 - Release
Active Call,
Accept Held
Call
1x - Release
Active/Held
Call x from
MTPY Call
2 - Switch
Between
Held and
Active Call
2x - Active
MTPY Call to
Hold, Except
for Call x
3 - Add Held
Call to
Active Call