Technical documentation ❯

AT Commands

Command	Response	Description
AT+IPR?	+IPR: 0 OK	Port speed: 0 – auto 1200 2400 4800 9600 19200 38400 57600 115200
AT+ICF?	+ICF: 3,3 OK	Transmission settings. First parameter: Bits/parity/stop bits 1 – 8/0/2 2 – 8/1/1 3 – 8/0/1 4 – 7/0/2 5 – 7/1/1 6 – 7/0/1 Second parameter – parity: 0 – odd 1 – even 3 – none
AT+IFC?	+IFC: 0,0 OK	Flow control First parameter – terminal controlled by module Second parameter – module controlled by terminal 0 – none 1 – software (XON/XOFF) 2 – hardware (RTS/CTS)

Information and Status

Module Information

Command	Response	Description
AT+GCAP	+GCAP:+FCLASS,+CGSM OK	Module capabilities
AT+GMM	SIMCOM_SIM900 OK	Module identifier
AT+GMR	Revision:1137B09SIM900M64_ST OK	Firmware revision
AT+GSN	01322600XXXXXXX OK	IMEI

SR-Organizer-24-3

24 SIM cards, 3 GSM modems, headset and external device connection, Wi-Fi. Control via the local Web interface and the online control panel, GET and POST requests. Implement any workflows using user macros. Native Zennoposter support.

Module Status Information

Command	Response	Description
AT+COPS?	+COPS: 0,0,"MTS-RUS" OK	Operator information
AT+COPS=?	+COPS: (2,"MTS RUS","","25001"),(1,"MOTIV","MOTIV","25035"),(1,"Utel","Utel","25039"),,(0,1,4),(0,1,2) OK	Available operators
AT+CPAS	+CPAS: 0 OK	Module state 0 – ready 2 – unknown 3 – incoming call 4 – voice call in progress
AT+CREG?	+CREG: 0,1 OK	Network registration First parameter: 0 – disable network registration URC 1 – enable network registration URC 2 – enable URC with additional info Second parameter: 0 – not registered, no search 1 – registered, home network 2 – not registered, searching 3 – registration denied 4 – unknown 5 – roaming
AT+CSQ	+CSQ: 17,0 OK	Signal level: 0 – −115 dBm or less 1 – −112 dBm 2–30 – −110..−54 dBm 31 – −52 dBm or greater 99 – no signal
AT+CCLK?	+CCLK: "00/01/01,04:21:27+00" OK	Current date and time
AT+CBC	+CBC: 0,95,4134 OK	Supply voltage monitor First parameter: 0 – not charging 1 – charging 2 – charge complete Second parameter: 1–100 % — battery level Third parameter: Module supply voltage (VBAT), mV
AT+CADC?	+CADC: 1,7 OK	ADC value (up to 2.8 V)

Settings

Calls

Command	Response	Description
AT+CLIP=1	OK	Caller ID (CLIP) 1 – on / 0 – off
AT+GSMBUSY=0	OK	Block incoming calls 0 – allowed 1 – blocked
ATS0=0	OK	Auto answer 0 – manual 1 or more – auto after the specified number of rings

SR-Nano

500 or 1000 SIM cards, swappable modem module, headset connection, Wi-Fi. Control via the local Web interface and the online control panel, GET and POST requests. Multi-user mode. Implement any workflows using user macros. Native Zennoposter support.

SMS

Command	Response	Description
AT+CMGF=1	OK	Text mode 1 – enable 0 – disable see note
AT+CSCS= "GSM"	OK	Character set for text mode Available encodings: IRA, GSM, UCS2, HEX, PCCP, PCDN, 8859-1 see note
AT+CSCB=0	OK	Cell broadcast reception 0 – enabled (default) 1 – disabled

Misc

Command	Response	Description
ATE0	OK	Echo 1 – on (default) / 0 – off
ATV1	OK	Response format 0 – numeric result codes only 1 – verbose + echo (default)
AT+CMEE=0	OK	Error reporting 0 – disabled (default) 1 – numeric errors 2 – verbose errors
AT+CCLK="13/09/25,13:25:33+05"	OK	Set clock “yy/mm/dd,hh:mm:ss+zz” Where: year/month/day, hours:minutes:seconds +time zone
AT+CPIN=XXXX		Enter PIN code
ATZ0		Reset settings to defaults (not factory) 0 or 1 – profile selection
AT&F		Restore factory settings
AT&W	OK	Save settings to current profile Parameter 0 or 1 — select profile Specify parameter right after command (AT&W0)
AT+CPOWD=1	NORMAL POWER DOWN	Power off module 0 – urgent 1 – normal
AT+CFUN=1,1		Functional mode & reboot First parameter: 0 – minimum functionality 1 – full functionality (default) 2 – disable RF transmit/receive Second parameter: 0 – apply without reboot 1 – reboot (available only in full mode, i.e., 1,1)

SIM Bank

For 512 SIM cards, made of 8 compact swappable modules with 64 Nano-SIM each. For use with SR-Box aggregators of any model.

Phone Calls

Command	Response	Description
ATD+790XXXXXXXX;	OK	Dial number +790XXXXXXXX;
ATD+790XXXXXXXX;	NO DIALTONE BUSY NO CARRIER NO ANSWER	No dial tone Call rejected Call dropped No answer
ATDL	OK	Redial last outgoing number
ATA	OK	Answer call
ATH0	OK	Hang up / disconnect
	RING	Incoming call
AT+CLIP=1	OK	see settings
	RING +CLIP: "+790XXXXXXXX",145,"",,"",0	Incoming call with CLIP enabled Where: First parameter – caller’s phone number 2 – type of number (TON) 129 – unknown 161 – national 145 – international 177 – network/special

SMS

Commands are shown for text mode with GSM character set.

Command	Response	Description
AT+CMGS="+790XXXXXXXX" >Test sms. sim-roulette.com	> +CMGS: 15 OK	Send SMS. Specify the recipient’s number in quotes and send to the module followed by a line break (ASCII 13). After the “>” prompt, enter the message text. To send, finish with SUB (ASCII 26), or ESC (27) to cancel.
AT+CMGF=1 AT+CSCS= "GSM"		Mode and encoding. see settings and note
	+CMTI: "SM",4	New SMS indication. Second parameter is the index of the incoming SMS.
AT+CMGL="REC UNREAD"	+CMGL: 4,"REC UNREAD","+790XXXXXXXX","","13/09/24,23:02:22+24" Test2. OK	Read SMS by folder. There are 5 folders: REC UNREAD – inbox unread REC READ – inbox read STO UNSENT – user unsent STO SENT – user sent ALL – read all messages
AT+CMGR=2	+CMGR: "REC READ","+790XXXXXXXX","","13/09/21,11:57:46+24" Test sms. sim-roulette.com OK	Read an SMS. Request: First parameter – message index. Second parameter (optional): 0 – normal (default) 1 – do not change message status Response: First parameter – folder, see above. Second parameter – sender’s number 3 – sent date/time Then the message text follows.
AT+CMGDA="DEL SENT"	OK	Delete SMS by folder: DEL READ — read DEL UNREAD — unread DEL SENT — sent DEL UNSENT — unsent DEL INBOX — received DEL ALL — all messages
AT+CMGD=4	OK	Delete an SMS. First parameter – message index Second parameter: 0 – delete the specified message (default) 1 – delete read messages 2 – delete read and sent messages 3 – delete read, sent and unsent messages 4 – delete all messages
AT+CSCA?	+CSCA: "+79126313431",145 OK	Return SMSC (service center) number.

SR-Train

Unlimited number of SIM cards, 16 GSM modems, Wi-Fi. Control via the local Web interface and the online control panel, GET and POST requests. Multi-user mode. Implement any workflows using user macros. Native Zennoposter support.

DTMF

Tone keys: 0–9, #, *, A–D

Command	Response	Description
AT+VTD=3	OK	DTMF tone duration used by AT+VTS. Parameter value 1..255
AT+VTS="1,4,#,A,6,7,0"	OK	Send a DTMF sequence (up to 20 tones). Duration is set by AT+VTD.
AT+CLDTMF=7, "1,4,#,A,6,7,0"	OK	Play DTMF tones on the module (via audio out). First parameter — duration 1–100 Second parameter – tone string, up to 20.

USSD

Commands are shown for text mode with GSM character set.

Command	Response	Description
AT+CUSD=1,"#100#"	OK +CUSD: 0,"Balance:240,68r ",	USSD request First parameter – operation mode: 0 – send request, ignore response 1 – send request, return response 2 – cancel request Second parameter – request in quotes.
ATD#100#;	OK +CUSD: 0,"Balance:240,68r ",	Simplified USSD request (works only with GSM charset)

There are two USSD formats: starting with * and starting with #. In the first case, the response arrives in Russian; in the second, in Latin characters, if supported by the operator.
Display mode is the same as for SMS.

Note on text mode and encoding

The chosen mode (PDU or text) and character set affect the format of numbers, USSD requests, and incoming/outgoing SMS.

The most universal option is PDU mode, since it can reliably send/receive any text data; it is not covered here in detail.

The simplest option is the GSM character set. Numbers are entered in the usual numeric way; outgoing and incoming messages (SMS and USSD) in Latin are displayed correctly. Cyrillic is more complex: incoming messages appear in UNICODE, more precisely as UNICODE HEX values. Outgoing with Cyrillic are even trickier!

The more advanced option is UCS2. Incoming and outgoing messages, USSD requests, and phone numbers in requests — everything is written in UNICODE. Simplified USSD requests do not work.

Example (phone number replaced with +79012345678, line breaks added):

Encoding & mode	Request	Response
PDU	AT+CMGR=2	+CMGR: 1,"",38 07919720780110F0000B919710325476F800003190121 175644215D4F29C0E9AB7E72E50985DC6B7CAF8B24B5E07 OK
PDU	AT+CMGR=3	+CMGR: 1,"",59 07919720780110F0000B919710325476F800083190122 185134228005400650073007400200073006D00730020 0032002E0020042204350441044200200441043C0441 OK
GSM	AT+CMGR=2	+CMGR: "REC READ","+79012345678","","13/09/21,11:57:46+24" Test sms. sim-roulette.com OK
	AT+CMGR=3	AT+CMGR=3 +CMGR: "REC READ","+79012345678","","13/09/21,12:58:31+24" 005400650073007400200073006D007300200032 002E0020042204350441044200200441043C0441 OK
	AT+CUSD=1,"#100#"	OK +CUSD: 0,"Balance:240,68r ",
UCS2	AT+CMGR=2	+CMGR: "REC READ","002B0037003900300031 0032003300340035003600370038","","13/09/21,11:57:46+24" 005400650073007400200073006D0073002E0020 0061006C00650078002D006500780065002E00720075 OK
	AT+CMGR=3	+CMGR: "REC READ","002B00370039003000310032 003300340035003600370038","","13/09/21,12:58:31+24" 005400650073007400200073006D007300200032 002E0020042204350441044200200441043C0441 OK
	AT+CUSD=1,"00230031 003000300023"	OK +CUSD: 0,"00420061006C0061006E00630065003A0032 00340030002C0036003800720020",64

The text returned for “AT+CMGR=3” — “Test sms 2. Тест смс”

UNICODE

In Unicode, characters are represented as hexadecimal numbers. The first 127 characters map directly to HEX; for Cyrillic, an offset of 350h is applied.

Example: 1 – 0031, G – 0047, z — 007A, Ы — 042B, я — 044F

Authorization

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