User guide

Developers guidelines | AT commands
113 June 2010
AT+CHLD Call hold and multiparty (ver. 1)
<classx> Description
Integer Sum of integers each representing a class of infor-
mation.
Default value=3
1 Voice L1
2 Data
4 Fax
8 Short message service
16 Data circuit sync
32 Data circuit async
64 Dedicated packet access
128 Dedicated PAD access
<status>:
<status> Description
0 Not active
1 Active
Description: This command refers to a service that allows a call to be temporarily dis-
connected from the ME, but the connection is to be retained by the net-
work and to a service that allows multiparty conversation. Calls can be put
on hold, recovered, released and added to conversation similarly as
defined in GSM 02.30.
This is based on the GSM supplementary services HOLD (Call Hold) (refer
GSM 02.83 clause 2) and MPTY (MultiParty, see GSM 02.84). The interac-
tion of this command with other commands based on other GSM supple-
mentary services is described in the GSM standard.
Note: Call Hold and MultiParty are only applicable to teleservice 11.
It is recommended (although optional) that test command returns a list of
operations which are supported. The call number required by some opera-
tions will be denoted by “x”. For example, +CHLD: (0,1,1x,2,2x,3).
Set command: AT+CHLD=<n>
Test command: AT+CHLD=? Shows if the command is supported.
Test command
response: +CHLD: (list of supported <n>s)
Parameter:
<n>: Integer type. Equals numbers entered before SEND button in GSM 02.30
subclause 4.5.5.1.
<n> Description
0 Releases all held calls or sets User Determined
User Busy (UDUB) for a waiting call
1 Releases all active calls and accepts the other
(waiting or held) call