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GSM (SAT - 2) - 34

SIM Application Toolkit - SAT continued [Under GSM]
» ME-SIM interface, 11.11 «
» SAT, 11.14 «

Let us take an example which covers most of above SAT functionalities. Say operator provide a sub-menu item called Get weather info . When user select this, list of cities are to be shown (say Bangalore, Chennai, Delphi, Kolkota, and Mumbai). When user selects a city, SIM should trigger ME to send SMS W <city> to <certain number>. Network is to respond back with weather info in a normal SMS.

User powers on MS. ME activates the SIM. Once activated, SIM sends SET UP MENU command.
Response for FETCH
[Proactive command - SET UP MENU]
ME now adds this menu item to its menu list. After the execution of proactive SIM command, ME need to indicate result of execution to SIM (like command performed successfully). This is done by TERMINAL RESPONSE command.
Command contain menu information like menu title, menu items and their IDs etc.
[Response for SET UP MENU command]

Result code '90 00'
At some time, when user selects above operator's SAT menu and then item "Get weather info", ME informs this to SIM in ENVELOPE command.
Result code '91 XX'
XX is length of additional response data (proactive SIM command).

Response for FETCH
[Proactive command - SEND SMS]
ME may "notify" about this proactive session to user. User may in turn end the session. If so happen, ME should abort the procedure/session and inform to SIM that "Proactive SIM session terminated by the user" in TERMINAL RESPONSE.
This contain SMS L3 message ( SMS TPDU for SMS-SUBMIT or SMS-COMMAND) and SMS service center address. SMS L3 message contain number to which SMS is addressed and message itself.
User notified
We will assume that user do not end the session.
Say now MO SMS control is active. This forces ME to inform SIM about SMS being sent before triggering SMS procedure.
[MO SMS Control by SIM]
Contain number to which SMS is addressed and SMS service center number.
Response for ENVELOPE
[Response for MO SMS control]
SIM responds Allow with no modification . ME proceeds with MO SMS procedure.
L3 SMS message
ME sets up SMS connection and sends SMS. ME now need to inform SIM that SEND SMS has been performed successfully.
[Response for SEND SMS command]
Result code '90 00'
Network now sends SMS containing requested weather information. Of course, application is needed at network side (may be part of SMS service center) to send appropriate SMS back.
ME displays SMS to user (as done for all incoming SMSs).
L3 SMS message
This complete the example.

Another good example is of customer care number. Say this number is changed. How operator can take care of this without contacting the users. There are two ways to handle it:

1) Operator can send special type of SMS that is meant to be forwarded by ME to SIM. ME forwards such SMS to SIM with SAT procedure called Data download to SIM . SIM processes the proprietary information contained in SMS and updates customer care number in its (SIM) phone book. It informs change in phone book file with proactive command REFRESH. ME now reads related file from SIM with usual SELECT/READ RECORD commands. Now when user tries to dial customer care number (from SIM phone book shown by ME), the new number will dialed.

2) Above procedure will not work if user has stored customer care number in ME phone book. Here Call control by SIM is useful in addition to above procedure. SIM can modify this number to new number when ME informs it about outgoing call.

In next article, we will have quick look at proactive SAT command SET UP CALL.

References: None.

Copyright © Samir Amberkar 2010§

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