16.SUPPLEMENTARY SERVICES
16.13AT+CHLD Call Hold and Multiparty
Description | Command | Possible Responses | |
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Request call related | AT+CHLD=<n> | • | +CME ERROR <err> |
supplementary |
| • | OK |
services |
| • ERROR | |
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Show if the command | AT+CHLD=? | • | +CHLD: (list of |
is supported |
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| supported <n>s) |
• +CME ERROR <err>
• OK
• ERROR
This command allows control of the following call related services:
•a call can be temporarily disconnected from the ME but the connection is retained by the network;
•multiparty conversation (conference calls);
•the served subscriber who has two calls (one held and the other either active or alerting) can connect the other parties and release the served subscriber's own connection.
Calls can be put on hold, recovered, released, added to conversation, and transferred similarly as defined in 3GPP TS 22.030.
This is based on the GSM/UMTS supplementary services HOLD (Call Hold; refer 3GPP TS 22.083 clause 2), MPTY (MultiParty; refer 3GPP TS 22.084) and ECT (Explicit Call Transfer; refer 3GPP TS 22.091). The interaction of this command with other commands based on other GSM/UMTS supplementary services is described in the GSM/UMTS standards.
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 operations is denoted by “x” (e.g. +CHLD: (0,0x,1,1x,2,2x,3)).
<n> | Description |
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... | Integer type; equals to numbers entered before SEND |
| button in GSM 02.30 subclause 4.5.5.1 |
0 | Releases all held calls or sets User Determined User Busy |
| (UDUB) for a waiting call |
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0X | Releases a specific call X from a held multiparty call |
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1 | Releases all active calls (if any exist) and accepts the |
| other (held or waiting) call |
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1X | Releases a specific active call X |
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