Obile – Siemens MC55 User Manual
Page 231
MC55 AT Command Set
9.8 AT+CHLD
s
m
obile
MC55_ATC_V01.05
Page 231 of 469
2/10/04
Confidential / Released
1X
Terminate a specific call X (X= 1-7). The call may be active, held or waiting.
The remote party of the terminated call will receive a "NO CARRIER" indica-
tion. Parameter X is the call number
of the targeted call in the list of cur-
rent calls available with AT command
.
2
Place all active calls on hold (if any) and accept "the other call" as the active
call:
• If a call is waiting, the waiting call will be accepted.
• Otherwise, if a held call is present, the held call becomes active.
2X
Place all active calls except call X (X= 1-7) on hold. Parameter X is the call
number
of the targeted call in the list of current calls available with AT
command
.
3
Add a held call to the active calls in order to set up a conference (multiparty)
call.
Notes
• The
command offers a broad range of options according to the GSM specifications. However, if you
attempt to invoke an option which is not provisioned by the network, or not subscribed to, invocation of this
option will fail. The responses in these cases may vary with the network (for example "Operation not allowed",
"Operation not supported" etc.).
• This Supplementary Service is only applicable to Teleservice 11 (Speech telephony), that is, voice calls can
be put on hold, while data or fax calls cannot. For example, with
=2 you can simultaneously place a
voice call on hold and accept another waiting voice call. But it is possible to place a voice call on hold in order
to accept a waiting data of fax call, and afterwards recover the voice call. In this case, the only difference over
speech telephony is that the data or fax call needs to be manually accepted via
(see example below).
• In conflict situations, e.g. when a waiting call comes while there are already held calls, the above procedures
apply to the waiting call only. For example,
=0 rejects the waiting call, but does not affect the held calls.
• See also the
command for details on how to display waiting calls.
Example
^SYSSTART
at+cpin="9999"
OK
+CREG: 2
+CREG: 1,"0145","0016"
The mobile is now registered.
at+ccwa=1,1,1
You activate the indication of waiting calls during
voice calls.
OK
atd"1234567";
You make a voice call.
OK
+CCWA: "+491791292364",145,32,,0
You receive a URC indicating a waiting data call.
at+chld=2
You put the voice call on hold.
RING
You now receive the RING of the data call.