BGS2T AT Command Set
15.1 Usage of Remote-SAT
BGS2T_ATC_V01.301
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15.1
Usage of Remote-SAT
If SAT functionality is delivered by the SIM provider, the related SAT commands have to be handled. Otherwise
other SIM functionality may not working correctly (e.g. SMS-PP downloads).
Therefore two possible modes are available.
15.1.1
Automatic Response Mode (AR Mode)
If the ME operates in this (default) mode, usage of any Remote-Sat AT commands is not necessary. In this case,
all commands and responses are exchanged automatically between the ME and the SIM application. The type
of Terminal Response (TR) to a SAT Proactive Command issued by the SIM application used in AR mode is
listed at Table
, column "Auto Terminal Response". However, even while using AR
Mode it is crucial to react on SAT REFRESH Proactive Commands, indicating that data read from the SIM has
been changed!
Therefore, enable handling of
=
to get informed about SAT
REFRESH events.
Furthermore it is recommended to activate the
URC, because for SAT REFRESH Type SIM RESET
the same internally functionality as for physical remove and insertion of the SIM is done.
To take full advantage of Remote-SAT the ER mode has to be enabled using AT^SSTA=1. This setting is stored
non-volatile and takes effect after next switch-on of the ME.
15.1.2
Explicit Response Mode (ER Mode)
As a Wireless Modem does not have an MMI, Remote-SAT differs from a phone implementation of SAT. It uses
a special set of AT commands to pass data, e.g. a list of menu items, to the TE and to receive responses, e.g. a
selected menu item.
The TE is required to monitor the status of an ongoing SAT Proactive Command (PAC) and, if required, sends
appropriate AT commands, depending upon users input.
15.1.3
Character Sets
Strings are passed as UCS2 characters, but using the GSM alphabet is also possible. Use of GSM alphabet is
not recommended since a SIM can contain text which might be not displayable, e.g. greek characters. Use
AT^SSTA command to select the type of alphabet both for input and output. UCS is specified in ISO/IEC 10646.
There are 2 and 4 octet versions available, of which only the 2-octet variant is used, known as UCS2. The 65536
positions in the 2-octet form of UCS are divided into 256 rows, each with 256 cells. The first octet of a character
representation gives the row number, the second the cell number. The first row, row 0, contains exactly the same
characters as ISO/IEC 8859-1. The first 128 characters are thus the ASCII characters. The octet representing
an ISO/IEC 8859-1 character is easily transformed to the representation in UCS by putting a 0 octet in front of it.
UCS includes the same control characters as ISO/IEC 8859 which are located in row 0.
15.1.4
SIM Update Initiated by the Network
If a Customer Application (TE ) uses data of the SIM card please consider that the contents of all elementary files
are subject to change at any time. This happens because the network can change the SIM card data in the back-
ground via the SIM Application Toolkit (SAT) procedure "Data download to SIM". For a detailed description refer
to 3GPP TS 11.14
. In order to receive the information that an elementary file has been changed the TE has
to activate Remote SAT and needs to look for the SAT Proactive Command "REFRESH", Section
.
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