• Industrial GSM dual band modem.

• Power supply 8÷38Vdc 6÷29Vac.

• Data rate up to 14400bps. Fax/SMS.

• Extended AT commands.

• Mini-SIM card receptacle.

• R&TTE approval.

• RF power 2W @ EGSM900 (Class 4)

• RF power 1W @ GSM1800 (Class 1)

• Embedded antenna (type A)

• External antenna (type X)

Here is a simple BASCOM-AVR program that sends an SMS and will receive SMS:

'------------------------------------------------------------------------------
' SMS.BAS
' (c) 2002 MCS Electronics
' This sample shows how to use AT command on a GSM mode
' The GSM modems are available from www.mcselec.com
'------------------------------------------------------------------------------
'tested on a 2314
$regfile = "2313def.dat"

'XTAL = 10 MHZ
$crystal = 10000000

'By default the modem works at 9600 baud
$baud = 9600

'HW stack 20, SW stack 8 , frame 10

'some subroutines
Declare Sub Getline(s As String)
Declare Sub Flushbuf()
Declare Sub Showsms(s As String )


'used variables
Dim I As Byte , B As Byte
Dim Sret As String * 66 , Stemp As String * 6

'we use a serial input buffer
Config Serialin = Buffered , Size = 12 ' buffer is small a bigger chip would allow a bigger buffer

'enable the interrupts because the serial input buffer works interrupts driven
Enable Interrupts

'define a constant to enable LCD feedback
Const Uselcd = 1
Const Senddemo = 1 ' 1= send an sms
Const Pincode = "AT+CPIN=1234" ' pincode change it into yours!
Const Phonenumber = "AT+CMGS=+31653123456" ' phonenumber to send sms to

#if Uselcd = 1
 Cls
 Lcd "SMS Demo"
#endif

'wait until the mode is ready after power up
Waitms 3000

#if Uselcd = 1
 Lcd "Init modem"
#endif


Print "AT" ' send AT command twice to activate the modem
Print "AT"
Flushbuf ' flush the buffer
Print "ATE0"
#if Uselcd = 1
 Home Lower
#endif

Do
 Print "AT" : ' Waitms 100
 Getline Sret ' get data from modem
 #if Uselcd = 1
 Lcd Sret ' feedback on display
 #endif
Loop Until Sret = "OK" ' modem must send OK
Flushbuf ' flush the input buffer
#if Uselcd = 1
 Home Upper : Lcd "Get pin mode"
#endif
Print "AT+cpin?" ' get pin status
Getline Sret
#if Uselcd = 1
 Home Lower : Lcd Sret
#endif
If Sret = "+CPIN: SIM PIN" Then
 Print Pincode ' send pincode
End If
Flushbuf
#if Uselcd = 1
 Home Upper : Lcd "set text mode"
#endif
Print "AT+CMGF=1" ' set SMS text mode
Getline Sret ' get OK status
#if Uselcd = 1
 Home Lower : Lcd Sret
#endif

'sms settings
Print "AT+CSMP=17,167,0,0"
Getline Sret
Print "AT+CNMI=0,1,2,0,0"
Getline Sret

#if Senddemo = 1
 #if Uselcd = 1
 Home Upper : Lcd "send sms"
 #endif
 Print Phonenumber
 Waitms 100
 Print "BASCOM AVR SMS" ; Chr(26)
 Getline Sret
 #if Uselcd = 1
 Home Lower : Lcd Sret 'feedback
 #endif
#endif


'main loop
Do
 Getline Sret ' wait for a modem response
 #if Uselcd = 1
 Cls
 Lcd "Msg from modem"
 Home Lower : Lcd Sret
 #endif
 I = Instr(sret , ":") ' look for :
 If I > 0 Then 'found it
 Stemp = Left(sret , I)
 Select Case Stemp
 Case "+CMTI:" : Showsms Sret ' we received an SMS
 ' hanle other cases here
 End Select
 End If
Loop ' for ever


'subroutine that is called when a sms is received
's hold the received string
'+CMTI: "SM",5
Sub Showsms(s As String )
 #if Uselcd = 1
 Cls
 #endif
 I = Instr(s , ",") ' find comma
 I = I + 1
 Stemp = Mid(s , I) ' s now holds the index number
 #if Uselcd = 1
 Lcd "get " ; Stemp
 Waitms 1000 'time to read the lcd
 #endif

 Print "AT+CMGR=" ; Stemp ' get the message
 Getline S ' header +CMGR: "REC READ","+316xxxxxxxx",,"02/04/05,01:42:49+00"
 #if Uselcd = 1
 Lowerline
 Lcd S
 #endif
 Do
 Getline S ' get data from buffer
 Select Case S
 Case "PORT" : 'when you send PORT as sms text, this will be executed
 #if Uselcd = 1
 Cls : Lcd "do something!"
 #endif
 Case "OK" : Exit Do ' end of message
 Case Else
 End Select
 Loop
 #if Uselcd = 1
 Home Lower : Lcd "remove sms"
 #endif
 Print "AT+CMGD=" ; Stemp  ' delete the message
 Getline S ' get OK
 #if Uselcd = 1
 Lcd S
 #endif
End Sub


'get line of data from buffer
Sub Getline(s As String)
 S = ""
 Do
 B = Inkey()
 Select Case B
 Case 0 'nothing
 Case 13 ' we do not need this one
 Case 10 : If S <> "" Then Exit Do ' if we have received something
 Case Else
 S = S + Chr(b) ' build string
 End Select
 Loop
End Sub

'flush input buffer
Sub Flushbuf()
 Waitms 100 'give some time to get data if it is there
 Do
 B = Inkey() ' flush buffer
 Loop Until B = 0
End Sub