Chapter 14 – SIM ToolKit
Multi-Tech Systems, Inc. CDMA Wireless AT Commands (PN S000294J)
90
Call control by SIM
The call control mechanism allows the SIM to check all dialed numbers, supplementary service control strings and USSD
strings before connecting to the network. This gives the SIM the ability to allow, bar or modify the string before the operation
starts.
The commands used for this operation are:
+STCR
(SIM Toolkit Control Response)
+STGR
(SIM Toolkit Give Response)
Messages Exchanged During a SIM ToolKit Operation
The following scheme shows the SIM Toolkit commands and unsolicited results that are exchanged.
Step One
The customer application informs the modem which facilities are supported. This operation is performed with the
+STSF
(SIM
ToolKit Set Facilities)
command, which is also used to activate or deactivate the SIM Toolkit functionality.
Step Two
An unsolicited result
+STIN
(SIM ToolKit indication)
is sent by the product to indicate the customer application which command
type the SIM Application Toolkit is running on the SIM card. The last SIM Toolkit indication can be requested by the
+STIN?
command.
Step Three
The customer application uses the
+STGI
(SIM ToolKit Get Information)
command to get all the information about the SIM
ToolKit command, given by
+STIN
.
Step Four
The customer application uses the
+STGR
(SIM Toolkit Give Response)
to send its response
(if any)
to the SIM ToolKit
Application.
The
+STCR
(SIM Toolkit Control response)
indication is an unsolicited result sent by the SIM when call control functionality is
activated and before the customer application has performed any outgoing call, SMS, SS, or USSD.
MULTI-TECH
Modem
Customer
Application
+STSF=X,XXXXXXXX
+STIN=X
+STGI=X
+STGI response
+STGR=X,XXXXXX
STEP 1: Configuration and Activation
STEP 2: SIM sends pro-active command
STEP 3: Customer application gets all the information.
STEP 4: User response is sent to the SIM.
+STCR:X