Practical Example 1.3.2 : OutgoingVoice Call

This example illustrates the use of AT commands related to outgoing voice calls. In the example the usual interrogation commands are used to make sure the module is registered onto the network. Signal strength and SIM authentication checks are also done. In the script below, the module is configured for use with the Votronic handset (reference handset). Calls are made from the module and different configuration commands are explored with the outputs are given.

ati//Display product identification information – module and revision are presented

SIEMENS

MC55

REVISION 04.00

OK

at+cpin?//Check whether network authentication is required. Module is ready for use

+CPIN: READY

OK

at+cops?//Query present status of module’s network registration. Module has been

+COPS: 0,0,"VodaCom-SA"//authenticated on the Vodacom Network

OK

at+csq//Query quality of received signal strength and channel bit error rate

+CSQ: 26,99

OK

at+cmee=2//Set mobile equipment error message format to verbose mode (strings)

OK

at^snfs=1//Select audio hardware set for connected equipment ie. handset

OK//The module is set up for use with the Votronic reference handset

at^saic?//Check configuration of audio interface. In this case analog I/O

^SAIC: 2,1,1//will be used. Microphone 1 and earpiece amplifier 1 are used for the handset

// NOTE: These are the default settings on the module and do not have to be re-defined. This was done for completeness.

OK

at^snfw//Write these audio settings to non-volatile memory

OK

atd0116522872;//Originate a call. NOTE: The ‘;’ is important for voice calls – it is left out for data calls

//An attempt was made to enter in the command “AT+CLCC” before the OK from the ATD command was presented. This brings us to another feature on the modules. While operating in default mode (AT^SM20=1), the “OK” response will only be presented once a successful connection has been established or failure thereof has been determined. No other AT commands can be entered before the occurrence of the “OK” response. There might however, be cases where it is required to interrogate the module before the “OK” response is issued ie. before a connection has actually been established. In these cases, is becomes necessary to change the way in which the module handles the presentation of the “OK”. By changing the module to issue an “OK” immediately after the ATD command allows us time to interrogate the module before the call is actually set up.

NO DIALTONE//In this case, since an AT command was issued before the “OK” response, the NO DIALTONE URC was presented.

at^sm20=0//Change the response mode of the module to display “OK” immediately after the ATD command is issued.

OK

atd0116522872;//Dial the number again

OK//OK response follows immediately after ATD command is issued.

at+clcc//List current calls of the mobile equipment

+CLCC: 1,0,2,0,0,"0116522872",129//Response indicating that the call has been assigned a call identification number 1 (1).

//The call is a mobile originating call (0), and is currently dialing the number requested. (2)

//The call type is voice (0) and it is a non-multi party/conference call (0).

//The CLIP information is also presented here. In this instance, we can see that the call number is NOT presented

//in International format (129).

OK

at+clcc//List current calls of the mobile equipment

+CLCC: 1,0,3,0,0,"0116522872",129//Here the call is alerting the called party (3)

OK

at+clcc//List current calls for the mobile equipment

+CLCC: 1,0,0,0,0,"0116522872",129//The call has been accepted by the called party (second 0)

OK

//HERE THE CALLED PARTY TERMINATED THE CALL

NO CARRIER //URC indicating that the call has ended

at+clcc//List current calls – no calls in progress, so only “OK” response returned

OK

at^slcd//Query duration of last call

^SLCD: 00:00:07//Call lasted 7 seconds

OK

atdl;//Re-dial the last number dialed. Remember the ‘;’

OK

at+clcc//List current calls – these parameters will be the same as those returned previously

+CLCC: 1,0,2,0,0,"0116522872",129

OK

at+clcc

+CLCC: 1,0,3,0,0,"0116522872",129//List current calls – these parameters will be the same as those returned previously

OK

at+clcc

+CLCC: 1,0,0,0,0,"0116522872",129//List current calls – these parameters will be the same as those returned previously

OK

at+chup//Hang up the call. This command has the same functionality of the ATH command, the only restriction being that it

OK// cannot be used for fax calls.

at+clcc//List current calls

OK

at^slcd//Query duration of last call

^SLCD: 00:00:09//Call lasted 9 seconds

OK

at^smso//Shut down module gracefully

^SMSO: MS OFF//Response indicating that the terminal is powering down

OK

^SHUTDOWN//URC indicating that the terminal can be powered down in less than 1 second