constant definition Const Gsm_center = "+8613800210500" //SMS center number Const Send_number = "13916315573" //Phone number the SMS sends to Const Sms_texts = "My SMS Message" //Message texts to be send //Initialize the GSM module Print "AT+CMGF=1" //Set GSM module in Text mode Print "AT+CSCA=" ; Chr(34) ; Gsm_center ; Chr(34) //Set SMS center number //Send a message Print "AT+CMGS="; Chr(34); Send_number; Chr(34); Chr(13); Sms_texts; Chr(26) //Read and delete an incoming short message Print "AT+CMGR=1" //Read first short message from SIM card storage Gosub Rs232_r //Receive message Print "AT+CMGD=1" //Delete message from SIM card storage Listing 1—We created a program to send an SMS message to a mobile phone (13916315573). The program directs the GPS-GSM Mobile Navigator to read and delete an incoming short message. The Print command is a BASCOM-AVR instruction that sends output to the serial port. The Rs232_r subroutine is used to read input from the serial port.