This video describes how to connect a GSM SIM300 module with Arduino & make a call or send SMS. <br />The AT commands are sent from Arduino to GSM to achieve this.Sample sketch of making a call & sending SMS is explained. <br />Generally the thumb rule of connection is TX to Tx & Rx to Rx between Arduino & GSM.The GSM board used here for demo has RS232 circuit on board & the Tx/Rx of MAX232 IC is printed & not that of GSM. <br />This is the reason for connecting straight between the boards.Remember the thumb rule of connection is always Tx to Rx & Rx to Tx. <br /> <br />http://alselectro.wordpress.com/2013/02/07/arduino-with-gsm/ <br /> <br />www.alselectro.com
