FARGO electronic Maestro 900 - Manual (Page 16)

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4. REMOTE AT COMMAND BY SMS
This feature is to control the modem to interpret AT command from incoming SMS, executing it,
and return the result to sender by SMS.
The user can enable the modem to receive AT command by incoming SMS. See following about
AT+SMSAT command.
4.1 Description of the Operation
1. When enabled, the modem will treat the incoming SMS as a source of AT command only if
all of the following conditions (a,b and c) are fulfilled :
a. The content of SMS sent to the modem is using standard 7-bit GSM data decoding scheme,
b. The first 6 characters of the SMS content matches the <key> parameter set by AT+SMSAT
command, (default key is “000000”)
c. The 7 th and 8 th characters of the SMS content is “AT” (in capital letters)
2. If SMSAT is enabled , the modem will read each incoming SMS, if the conditions mentioned in 1
are matched the message will be executed, even it is an invalid AT command
3. When using SMSAT feature, only +CNMI:x,1,x,x,x setting could be used (i.e. incoming message
will be stored in SIM card). If the incoming SMS is treated as with AT command inside, the SMS
will be deleted after execution. If not the modem will leave it in SIM, just like normal SMS.
4. The maximum length of the AT command is limited by length of SMS, i.e. 160-6 = 154 characters
5. When the SMS AT command is executed , all intermediate and final responses will be buffered
recorded, then return to the sender’s phone number in one single SMS.
6. If response(s) of the AT command is(are) more than 160 characters, only the first 160 characters
will be returned.
7. In case the modem cannot get terminal response within 26 seconds, the modem will then abort
the command, and return intermediate responses (if present).
8. If SMSAT feature is enabled all incoming SMS, either with valid AT command or not, will be
erased. This is to prevent SIM card memory from fully filled, such the modem will not receive
new SMS.
+CSQ: 17,0 OK
Step 1 : send AT command
to modem by SMS
000000AT+CSQ
Step 2 : modem execute and
return response by SMS