Specifications

Chapter 12 – Short Message Service (SMS) Commands
Multi-Tech Systems, Inc. AT Commands for EDGE (E1) Modems (S000474A) 220
12.7 AT+CMGS Send SMS Message
Description: The write command transmits a short message from TE to network (SMS-SUBMIT). After
invoking the write command, wait for the prompt “>”, and then start to write the message. To
send the message simply enter <CTRL-Z>. After the prompt, a timer will be started to observe
the input.
To abort sending use <ESC>. Abortion is acknowledged with “OK”, though the message will not
be sent.
The message reference <mr> is returned to the TE on successful message delivery. The value
can be used to identify the message in a delivery status report provided as an unsolicited result
code.
Syntax: Test Command: AT+CMGS=?
Response: OK
Write Command: If text mode (see AT+CMGF=1)
AT+CMGS=<da>[, <toda>]<CR> Text can be entered. <CTRL-Z>/<ESC>
Response: +CMGS: <mr>[, <scts>]
OK
If sending fails see notes below.
Write Command: If PDU mode (see AT+CMGF=0)
AT+CMGS=<length><CR> PDU can be entered. <CTRL-Z>/<ESC>
Response: +CMGS: <mr>[, <ackpdu>]
OK
If sending fails see notes below.
Notes:
• If sending fails, for example, if a message is too long, the result code depends on the current setting of the
AT^SM20 command:
If the AT^SM20 <CmgwMode> equals 1 (factory default) any failure to send a message is responded with
"OK".
Users should be aware, that despite the "OK" response, the message will not be sent to the subscriber.
If the AT^SM20 <CmgwMode> equals 0 any failure to send a message is responded with "ERROR".
• If sending fails due to timeout, then
AT^SM20 <CmgwMode>=1 causes "+CMS ERROR: unknown error" to be returned;
AT^SM20 <CmgwMode>=0 causes "+CMS ERROR: timer expired" to be returned.
• Note that some providers do not recognize an @ symbol used in a short message. A widely used alternative is
typing “*” as defined in GSM 03.40 (GPP TS 23.40).
• All characters entered behind the prompt “>” will be recognized as GSM characters. For example, “Backspace”
(ASCII character 8) does not delete a character, but will be inserted into the short message as an additional
physical character. As a result, the character you wanted to delete still appears in the text, plus the GSM code
equivalent of the Backspace key.
• Message Length in Text Mode
The maximum length of a short message depends on the used coding scheme: It is 160 characters if the 7 bit
GSM coding scheme is used, and 140 characters according to the 8 bit GSM coding scheme. In case UCS2
character set selected it is highly recommended to set Data Coding Scheme (<dcs> of AT+CSMP) to 16-bit data,
otherwise the length of SMS user data is restricted to 88 octets. Even better for messages with UCS2 character
set is the PDU Mode.
• At baud rates lower than 19200 it is recommended to use the line termination character only (refer to <n> of
ATS3, default <CR>) before entering text or PDU. Use of the line termination character followed by the response
formatting character (see <n> of ATS4, default <LF>) can cause problems.
• During a pending USSD user interaction the AT+CMGS write command returns "+CME ERROR: operation
temporary not allowed" to prevent blocking situations.
• This command is PIN protected.
• This command is not supported in airplane mode.