MC52i AT Command Set

MC52i AT Command Set
10.9 AT^SIST
10.9 AT^SIST Enter Transparent Access Mode
The AT^SIST command applies only to the Transparent service defined with AT^SISS. It can be used after the
Transparent service has been opened with AT^SISO and is in "Up" state (=4). If the service is not
"Up" trying to open it will be denied with "+CME ERROR: operation temporary not allowed".
There are two ways to verify that the service is "Up": Each time after opening the service with AT^SISO wait for
the "^SISW: x, 1" URC (if URC mode is enabled). In addition, or when using Polling mode, you can request the
with AT^SISO or AT^SISI.
Then, after entering the AT^SIST command, the CONNECT response notifies that the service has entered transparent
access mode and is ready to transparently send and receive payload data over the serial interface. In this
mode, the signaling of URCs is dependent on the settings made with AT^SCFG, parameter .
There are several ways to quit the transparent access mode and revert to AT command mode:
• +++ escape sequence (also transmitted over the air)
• DTR ON-OFF transition (see AT&D for configuring DTR line)
• "etx" parameter set within the server address for transparent access mode (see AT^SISS,
"address".
Switching back and forth between both modes does not affect the underlying socket and has no influence on the
service .
The Transparent service remains in 4 ("Up") until closed with AT^SISC or released by the server.
If the Transparent service is released by the server the following applies:
• If the service is in transparent access mode (CONNECT mode): ME returns to AT command mode, issues a
specific "NO CARRIER" result code and goes to 6 ("Down"). The "NO CARRIER" result code
starts with 0x10 (DLE) and 0x04 (EOT) and ends with the characters defined by ATS3 and ATS4.
• If the service is in AT command mode and no data is pending: "^SIS" URCs notify the client that the server
has disconnected and the ME goes to 6 ("Down").
• If the service is in AT command mode and data is still available: "^SIS" URCs notify the client that the server
has disconnected and the service remains in 5 ("Closing"). In this case the client shall open the
transparent access mode with AT^SIST. After the CONNECT response, all remaining data can be transferred.
• In all above scenarios, the Transparent service shall be closed with AT^SISC after it has gone to
6 ("Down"). Trying to return to transparent access mode with AT^SIST would only end up with
"NO CARRIER" once again and is not recommended.
• Use AT^SISO and AT^SISI to check the .
• Please note that the "^SIS" URCs mentioned above vary with the network. There may be for example "^SIS"
URCs with 15 ("Remote host has reset the connection") and 19 ("Socket has been shut
down). See Section 10.11, Internet Service URC "^SIS" for a list of possible URCs.
Syntax
Test Command
AT^SIST=?
Response(s)
OK
Write Command
AT^SIST=
Response(s)
CONNECT
(indicates that ME has entered transparent access mode)
OK
MC52i_ATC_V01.201 Page 258 of 551 4/16/10
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