AC75 AT Command Set
9.8 AT+CHLD s
AC75_ATC_V01.002 Page 240 of 569 10/30/06
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9.8 AT+CHLD Call Hold and Multiparty
Syntax
Command Description
TA controls the Supplementary Services Call Hold and Multiparty. Calls can be put on hold, recovered, released,
and added to a conversation.
Like for all Supplementary Services, the availability and detailed functionality of Call Hold and Multiparty services
depends on the configuration of the GSM network. The AC75 can only request the service, but the network
decides whether and how the request will be answered.
Parameter Description
0 Release all held calls or set User Determined User Busy (UDUB) for a waiting
call:
• If a call is waiting, release the waiting call. The calling party will receive a
"BUSY" indication (Supplementary Service User Determined User Busy
"UDUB")
• Otherwise, terminate all held calls (if any).
1 Terminate all active calls (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.
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 <idx> of the targeted call in the list of cur-
rent calls available with AT command AT+CLCC.
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 <idx> of the targeted call in the list of current calls available with AT
command AT+CLCC.
3 Add a held call to the active calls in order to set up a conference (multiparty)
call.
Test Command
AT+CHLD=?
Response(s)
+CHLD: (list of supported <n>s)
OK
Write Command
AT+CHLD=[<n>]
Response(s)
OK
ERROR
+CME ERROR: <err>
Reference(s) PIN ASC0 ASC1 USB MUX1 MUX2 MUX3 Charge 4Last
GSM 07.07 + + + + + + + - - -
<n>(num)