iTegno 39XX GPRS Modem
AT Commands Guide
02000C17
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v1.5
Confidential
All specifications are correct at the time of release. iWOW Connections owns the proprietary rights to the information contained herein this
document. It may not be edited, copied or circulated without prior written agreement by iWOW Connections Pte Ltd. © 2011, 2012 iWOW
Connections Pte Ltd
114
8.8
Call Hold +CHLD
Description:
This command allows to managing call hold and multiparty conversation (conference call).Calls can be put on
hold, recovered, released or added to conversation.
Note: Call Hold, Multi Party and Explicit Call Transfer are only applicable to tele service 11.
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Using Set command calls can be put on hold, recovered, released, added to conversation, and transferred.
This is based on the GSM/UMTS supplementary services HOLD, MPTY (i.e Multi Party) and ECT (Explicit
Call Transfer). The interaction of this command with other commands based on other GSM/UMTS
supplementary services is described in the GSM/UMTS standards.
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Test command returns a list of operations which are supported. The call number required by some
operations shall be denoted by “x” (e.g. +CHLD: (0, 1, 1x, 2, 2x, 3)).
Syntax:
AT+CHLD=[<n>]
Command
Possible Responses
AT+CHLD=[<n>]
OK
or
+CME ERROR: <err>
AT+CHLD=?
+CHLD: (list of supported <n>s)
OK
Defined Values
<n>
0
Release all held calls or set User Determined User Busy (UDUB) for a waiting call
1
Release all active calls (if any exist) and accepts the other (held or waiting) call
Note: In the scenario: An active call, a waiting call and held call, when the active call is terminated, we will
makethe Held call as active.
1X
Release a specific call X (active call)
2
Place all active calls (if any exist) on hold and accepts the other (held or waiting) call.
2X
Place all active calls on hold except call X with which communication is supported.
3
Adds a held call to the conversation.
4
Connects the two calls and disconnects the subscriber from both calls (Explicit Call Transfer)
6
puts an active call on hold or an held call to active, while another call is waiting
7
disconnect users in multiparty without accepting incoming call
8
release all calls