SimCom RS-232 User manual

SIM900A GSM/GPRS Modem
(RS-232)

Description:
This modem is built with SIMCOM SIM900A a Dual-band
GSM/GPRS engine.
The Modem is designed with RS232 level converter
circuitry, which allow user to directly interface with serial
port of computer.
Default modem is inAuto baud rate mode, can be configure
it from 9600-115200using AT commands.
Supports Serial port(RS232), Audio interface, RTC,
Phonebook Management.
Internal TCP/IP stack to enable internet via GPRS.
Supports SMS as well as DATA transfer application in M2M
interface.
As far as design concerned, it is very compact design and
easy to use.
Widely used in wireless communication projects.

Features:
SupplyVoltage: 5-12V DC.
Temperature range : -30 DegC to +80 DegC.
LED
indication for power and network status.
Onboard switching typepower supply regulator with Buzzer to
indicate Call Alerts.
Transmitting power: - Class4 (2W).
- Class1 (1W).
GPRSConnectivity: -GPRS multi-slot class10 (default)
- GPRS multi-
slot class8 (option)
Supports
CSD, USSD, SMS, FAX (Group 3 Class 1).
Single
SIM card and SMA connector with GSM Antenna.
Serial port(RS232) output and supports for Audio interface,
RTC,Phonebook Management.

ConnectionDetails

ConnectionDetails
Sr. No. Connection/ Terminal Details Note
1DCJack(X8) DCInput 7-15VDC Input
2DB9FemaleConn(X4) RS232Connector
3RJ11-4Conn(X3) AudioConnector
4TX (X1-1) TransmitPin of SIM900
5RX (X1-2) Receive Pin of SIM900
6ADC (X2-1) ADC Input Pin InputVoltage Range 0V to 2.8VDC
7RTC(X2-2) PowerSupply for RTC 3VExternal Battery
8DTX (X2-3) DebugTx fordebugging and upgrading
firmware
9RTX(X2-4) DebugRx
10GND(X2-5) Ground CircuitGround
11+5V (X2-6) +5VDCOutPin +5DC200mAMax
12POUT(X3-1) NC
13DTR(X3-2) DataTerminalReady
14DCD(X3-3) DataCarrier Detect
15DBR (X3-4) NC
16CTS(X3-5) Cleartosend
17RTS(X3-6) Request toSend
18SCL(X4-1) I2CSerialBus Data
19SDA(X4-2) I2CSerialBus Clk
20PWM1(X4-3) PWM1OUT
21PWM2(X4-4) PWM2OUT

Examples:
On HyperTerminal connect modem with setting as below :
baudrate:9600,
parity: None,
data bits: 8,
stop bits:1
All commands should be executed by pressing “Enter’ button.
To check Communication of modem:
command: AT
Reply: OK
Make Call:
command: ATD975648XXXX;
Reply: OK
AnswerCall:
command: ATA
Reply: OK
DisconnectCall:
command: ATH
Reply: OK

SendSMS :
1) Set SMS configuration(Text mode only once):
command: AT+CMGF=1
Reply: OK
2) Send SMS :
command: AT+CMGS=“[phone]XXXX”
>This is a test SMS<Ctrl+z>
Reply: +CMGS:45
OK
Read SMS (location no: 1):
command: AT+CMGR=1
Reply: +CGMR: “REC UNREAD”,” 91975648XXXX”
,””,”02/03/15,20:30:31+00”
This is test SMS
OK
Read SMS (location no: 2):
command: AT+CMGR=2
Reply: +CGMR: “REC UNREAD”,” 91975648XXXX”
,””,”02/03/15,20:30:31+00”
Hello how are you test SMS
OK

Delete SMS at location 1:
command: AT+CMGD=1
Reply: OK
To Delete All SMS:
command: AT+CMGDA=“DEL ALL”
Reply: OK
To Read all SMS :
command: AT+CMGL=“ALL”
Reply: +CGML: 1,“REC READ”,” 91 975648XXXX”
,””,”02/03/15,20:30:31+00”
This is test SMS
OK
+CGMR: 2,“REC UNREAD”,” 91 975648XXXX”
,””,”02/03/15,20:30:31+00”
Hello how are you test SMS
OK
Note: For more details go to “www.google.com”and search for
“SIMCOM SIM900A AT Command”. For SIM900A Datasheet
“www.simcom.us/act_admin/supportfile/SIM900_ATC_V1.00.pdf”