GSM Modem Interface?

ironclaw

HI Folks,

Been messing around with a new GSM terminal I got (Siemens TC35i) with HyperTerminal AT commands and it got me thinking. Is there script that one could write where by:

It could recieve an SMS to interrogate a Serial Port to determine if a switch is closed or open, and then report this by reply SMS?

A predetermined SMS sent to it could switch a relay attached to a Serial Port?

Any ideas?

Thanks,

ironclaw

Tom Dunne

ironclaw wrote: »

HI Folks,

Been messing around with a new GSM terminal I got (Siemens TC35i) with HyperTerminal AT commands and it got me thinking. Is there script that one could write where by:

It could recieve an SMS to interrogate a Serial Port to determine if a switch is closed or open, and then report this by reply SMS?

A predetermined SMS sent to it could switch a relay attached to a Serial Port?

Any ideas?

What languages do you know, and can they interact with the serial port?

By the sounds of it, you need code to send/receive the SMS, code to interpret the contents of the SMS and code to send/receive to/from the serial port.

Easy.

ironclaw

Tom Dunne wrote: »

What languages do you know, and can they interact with the serial port?

By the sounds of it, you need code to send/receive the SMS, code to interpret the contents of the SMS and code to send/receive to/from the serial port.

Easy.

Have a rough idea of a few languages. What would be best in your opinion? Its going to be running on an XP machine.

Tom Dunne

ironclaw wrote: »

Have a rough idea of a few languages. What would be best in your opinion? Its going to be running on an XP machine.

C++ would be the obvious one.

I don't know enough about Java/C# to say if they would be any good for something like this.

ironclaw

Tom Dunne wrote: »

C++ would be the obvious one.

I don't know enough about Java/C# to say if they would be any good for something like this.

Thats the road I was sorta taking myself. Summer project so

matrim

You could check out an opensource project called kannel which is an SMS gateway.

It would probably be a good place to get some info on the SMS processing

ironclaw

matrim wrote: »

You could check out an opensource project called kannel which is an SMS gateway.

It would probably be a good place to get some info on the SMS processing

I looked into it but it seemed more web based. I'm looking for something that will read a text and perform a command based on the content e.g. Close a relay.

Thanks for the info though!

DublinDilbert

ironclaw wrote: »

I looked into it but it seemed more web based. I'm looking for something that will read a text and perform a command based on the content e.g. Close a relay.

Thanks for the info though!

The Telus GSM modules will allow you to write/run scripts on them, to read/write i/o pins etc....

Most GSM modules are dumb devices, which you need to control over the serial port (using AT commands), typically from an embedded micro controller, which would do the reading of I/O etc...

onedmc

Does it not ship with an Active Expert API. I think that other Siemens terminals used to.

ironclaw

onedmc wrote: »

Does it not ship with an Active Expert API. I think that other Siemens terminals used to.

I think thats extra. I got it off a mate who was throwing it out funnily enough.

DublinDilbert

You could get a small microchip/atmel dev kit and write a bit of C-code to spit out the AT commands etc.... If your not familiar with that side of things, it would be a good way to learn.

ressem

.Net would probably be easiest now that there exists System.IO.Ports.SerialPort , havn't tried it though.

----
Alternatives
In unix/linux you can do this sort of thing using CU, part of the UUCP package.

#install the cu program
yum install uucp
#set serial parameters
stty 19200 cs8 -parenb -cstopb crtscts echo -F /dev/ttyS0
#open terminal for scripting
cu -l ttyS0

There might be a version written for cygwin/ windows, or not.
----

In Java you can use the javax.comm library.
Sun have an old sample program SerialConnection.java which will help with the basics of setting up listeners
You set up the device to notify you when it gets a message. You just need to make sure to keep deleting out the old messages as there is a limit of about 10 stored on the device.

AT Commands you might make use of...

// Request Notification from TC35
   write("AT+CNMI=2,1,0,0\n");
   // Used to be AT+CNMI=2,1,0,0,0 but TC35 does not support last char = 0. Only 1
		
// List SMSes and their content from buffer
    write("AT+CMGL=\"ALL\"");


// @param message -- SMS Message content to send to the terminal
// @param destination -- destination number

    AT+CMGS=\""+destination+"\"\n
    // There should be a > response from the terminal, after which you write
    "message"+"\032"


//  Write the GSM AT+CMGF=1 command to the terminal.
// This is necessary after any start or restart of the terminal. 
// Otherwise texts will be returned in a machine readable GSM PDU format.

	AT+CMGF=1
			
// Delete Message
	AT+CMGD=<number>

Ginger

I did this in VB way back in 2001... Will see if I can dig up the code...

It was originally for the Siemens GSM modem, then I modded it for IR and Nokia phones..

Ginger

Oki doki dug out the code

2 simple VB functions

First one is the one reposible for setting up the modem and creating the commands.

This function just sends an SMS to a particlar number (using the Meteor exchange) change that number for yourself. Needs the modem to be on Com port 1

The main things to notice are the AT commands for sending the SMS message. You need to first establish the connection and then set the outgoing exchange number followed by the recipients number.

After that this is the doozy you need to send teh modem the SMS followed by ^z followed by the final command which will initiate the send to the number.

Public Function SendSMS(strRecipient, strSMS) As Boolean

MSComm1.CommPort = 1
MSComm1.Settings = "9600,N,8,1"
   
MSComm1.PortOpen = True
    
If Err Then
       SendSMS = False
       Exit Function
End If
    
Dim strCommandSet As String
  
strCommandSet = "AT+CMGF=1;" + vbCr
    
If (RunATCommand(MSComm1, strCommandSet, "OK")) Then
    strCommandSet = "AT+CSCA=" & Chr(34) & "+353857000000" & Chr(34) & ";" & vbCr
    If (RunATCommand(MSComm1, strCommandSet, "OK")) Then
        strCommandSet = "AT+CMGS=" & Chr(34) & strRecipient & Chr(34) & ";" & vbCr
        If (RunATCommand(MSComm1, strCommandSet, ">")) Then
            strCommandSet = strSMS & Chr(26)
            If (RunATCommand(MSComm1, strCommandSet, "OK")) Then
                SendSMS = True
            Else
                SendSMS = False
            End If
        Else
            SendSMS = False
        End If
    Else
        SendSMS = False
    End If
Else
    SendSMS = False
End If

MSComm1.PortOpen = False

End Function

This next function sends the command to the modem and checks the returns etc...

Function RunATCommand(objModem As MSComm, strCommand As String, strCompare As String) As Boolean
    
Dim blExitLoop          As Boolean
Dim varEvents           As Variant
Dim strModemString      As String

blExitLoop = False
    
If Len(strCommand) <= 0 Or Len(strCompare) <= 0 Then
    RunATCommand = False
    Exit Function
End If
    
objModem.InBufferCount = 0
objModem.Output = strCommand
    
Do While Not (blExitLoop)
    'varEvents = DoEvents
    
    If objModem.InBufferCount Then
        strModemString = strModemString + objModem.Input
                 
        If InStr(1, strModemString, "ERROR", vbTextCompare) Then
            blExitLoop = True
            RunATCommand = False
        End If
        
        If InStr(1, strModemString, strCompare, vbTextCompare) Then
            blExitLoop = True
            RunATCommand = True
        End If
    
    End If

Loop
    
End Function

Hope it helps