> 2.9.4 | CSD call handling – outgoing CSD calls

> This section comprises the subsections Description, Used AT Commands, Flow Chart, Hints and Example. To move to these subsections please use the Navigation Frame or the appropriate buttons on the toolbar.

> 2.9.4.1 | Description

> This chapter describes the handling of outgoing CSD calls. To dial out you may use the commands ATD, ATDI and ATDL. Do not attach a semicolon “;” at the end of the dial string.
> Dialing from the phonebooks is not supported for data connections.
> When dialing a data call number, the following responses can be returned:
> CONNECT (if ATX0) or CONNECT <text> (if ATX>0)
> NO CARRIER
> BUSY
> NO DIALTONE
> The response is given when the connection has been set up successfully ("CONNECT"), or when it fails ("NO CARRIER", "BUSY", "NO DIALTONE"). The settings of AT^SM20 do not apply to data calls.
> If the module is initialized with AT+CR=1, the additional intermediate result “+CR: REL ASYNC” appears before the CONNECT result code.
> When the TA-TE link is reserved, i.e. when the module is in data mode, any URCs, for example an incoming SMS, will be indicated by a BREAK only. The URC itself will be transmitted as soon as the TA-TE link is free again. This means, the URC will be output either when the user switches from data to command mode with +++, or when the line is dropped.

> 2.9.4.2 | Used AT commands

> Command | Explanation
> ATD | Mobile originated call to dial a number
> +++ | Switch from data mode to command mode
> ATO | Switch from command mode to data mode / PPP online mode
> ATH | Disconnect existing connection
> AT+CHUP | Hang up call

> For further details about the commands see [2].

> 2.9.4.3 | Flow chart

> Figure 57: CSD call handling - outgoing calls

> 2.9.4.4 | Hints

> Not applicable.

> 2.9.4.5 | Example

> Example 1:
> ***************************************
> Comment: CSD call handling - outgoing calls 1
> ***************************************
> ***************************************
> Comment: Subscriber 1 makes a CSD call to subscriber 2.
> ***************************************
> Subscr 1 Send: ATD2400022
> Subscr 1 Receive: ATD2400022
> Subscr 2 Receive:
> Subscr 2 Receive: +CRING: REL ASYNC
> ***************************************
> Comment: Subscriber 2 rejects the incoming call.
> ***************************************
> Subscr 2 Send: ATH
> Subscr 2 Receive: ATH
> Subscr 2 Receive: OK
> Subscr 1 Receive:
> Subscr 1 Receive: +CAUSE: 8:21
> Subscr 1 Receive: NO CARRIER
> Example 2:
> ***************************************
> Comment: CSD call handling - outgoing calls 2
> ***************************************
> ***************************************
> Comment: Subscriber 1 makes a CSD call to subscriber 2.
> ***************************************
> Subscr 1 Send: ATD2400022
> Subscr 1 Receive: ATD2400022
> Subscr 2 Receive:
> Subscr 2 Receive: +CRING: REL ASYNC
> ***************************************
> Comment: Subscriber 2 answers the incoming call.
> ***************************************
> Subscr 2 Send: ATA
> Subscr 2 Receive: ATA
> Subscr 2 Receive:
> Subscr 2 Receive: CONNECT 9600/RLP
> Subscr 1 Receive:
> Subscr 1 Receive: CONNECT 9600/RLP
> ***************************************
> Comment: Subscriber 1 changes to command mode.
> ***************************************
> Subscr 1 Send: +++
> Subscr 1 Receive:
> Subscr 1 Receive: OK
> Subscr 2 Receive: +++
> ***************************************
> Comment: Subscriber 1 hangs up connection.
> ***************************************
> Subscr 1 Send: ATH
> Subscr 1 Receive: ATH
> Subscr 1 Receive: OK
> Subscr 2 Receive:
> Subscr 2 Receive: +CAUSE: 8:16
> Subscr 2 Receive: NO CARRIER