Problem with AT send with GSM modem

[UmDois]

I have a GSM modem, Wavecom.
When I connect to it using HyperTerminal, i can send SMS with the standard AT comands, like this:

AT+CMGS="+351nnnnnnnnn" <CR>
> text to send in the message <Control-Z>

and the SMS goes on.

Note: <CR> means ENTER
Note: <CR> is ASCII 13, and Control-Z is ASCII 26.

When I use VisualBasic, the SAME AT sequence does not work.
And I get an ERROR (twice).

The manual says to do the following:

MSComm.Output = "AT+CMGS=" & chr(34) & "+ "+351nnnnnnnnn" & chr(34) & chr(13)

MsComm.Output = "text to send in the message" & chr(26).

Note: chr(34) is the character for the commas(").

What is wrong?

Many thanks for any help.

[willakawill]

Hi. You could try this

Const quote As String = """"
MsComm.Output = "AT+CMGS=" & quote & "+351nnnnnnnnn" & quote & vbCr

[Killer42]

I have a GSM modem, Wavecom.
When I connect to it using HyperTerminal, i can send SMS with the standard AT comands, like this:
AT+CMGS="+351nnnnnnnnn" <CR>
> text to send in the message <Control-Z>
and the SMS goes on.
When I use VisualBasic, the SAME AT sequence does not work.
And I get an ERROR (twice).
The manual says to do the following:
MSComm.Output = "AT+CMGS=" & chr(34) & "+ "+351nnnnnnnnn" & chr(34) & chr(13)
MsComm.Output = "text to send in the message" & chr(26).

A couple of questions...

• Are you certain that it's only a CR which is sent after the AT command?
• What error are you getting?
• What does the ">" represent on the second line? (I ask mainly because it is not present in the VB version.)
• Are you sure you're in command mode? I seem to recall (from more than 10 years ago, I think) that you have to pause for at least a second, then send "+++" then another pause, to go into command mode. But this probably only applies if you are online at the time, right?
• Is this code copied/pasted, or typed in here? Because
  MSComm.Output = "AT+CMGS=" & chr(34) & "+ "+351nnnnnnnnn" & chr(34) & chr(13)
  seems to have quotes in the wrong places. It probably should have been
  MSComm.Output = "AT+CMGS=" & chr(34) & "+351nnnnnnnnn" & chr(34) & chr(13)

You can also make the code much more compact and readable by using CONST values as willakawill suggested. (Oops! Didn't realise you'd also fixed the mixed-up quotes, Will.)

[willakawill]

Yeah. Get with it down there. You're supposed to be 13 hours ahead of me :)

[iburyak]

It looks like your error is here:


[PHP]"+ "+351nnnnnnnnn" [/PHP]

You have "+ twice.

[iburyak]

Try this:

MSComm.Output = "AT+CMGS=""+351nnnnnnnnn""" & chr(13)

MsComm.Output = "text to send in the message" & chr(26).

[willakawill]

Try this:

MSComm.Output = "AT+CMGS=""+351nnnnnnnnn""" & chr(13)

MsComm.Output = "text to send in the message" & chr(26).

You are posting the same answer that has already been posted by 2 others

[Killer42]

Yeah. Get with it down there. You're supposed to be 13 hours ahead of me :)

Yeah, well it's hard to forecast accurately what someone is going to say in 13 hours. ;)

[sirsnorklingtayo]

I have a GSM modem, Wavecom.
When I connect to it using HyperTerminal, i can send SMS with the standard AT comands, like this:

AT+CMGS="+351nnnnnnnnn" <CR>
> text to send in the message <Control-Z>

and the SMS goes on.

Note: <CR> means ENTER
Note: <CR> is ASCII 13, and Control-Z is ASCII 26.

When I use VisualBasic, the SAME AT sequence does not work.
And I get an ERROR (twice).

The manual says to do the following:

MSComm.Output = "AT+CMGS=" & chr(34) & "+ "+351nnnnnnnnn" & chr(34) & chr(13)

MsComm.Output = "text to send in the message" & chr(26).

Note: chr(34) is the character for the commas(").

What is wrong?

Many thanks for any help.

Hi friend,

I've been in that kind of situation before and I used VB6 too, I developed a computer program that will keep all the SMS to my database and reply back with some information.

Ok here is the answer, before i tried that using chr(13) because this is the equivalent for the new line but unfortunately i dont know why this chr(13) is not working in MSCOM, but the only thing left is the constant value of VBCRLF you can use this as a substitute in chr(13)

Inshort

chr(13) = VBCRLF

and dont forget to send +++ it means that you will set the GSM in Command mode. Some1 already post this one, you better be careful in sending AT Command always keep in mind that before sending another batch of command you need to wait just for a second or 2, just use Sleep function in VB6.

Actually, after I solved that problem reagrading GSM and MSCOMM I realized that ANSI C is the much better language to use beacuse it is very easy to communicate with Devices like GSM. I am just telling you this because I experienced that before, but it will work fine in VB6 with MSCOMM


Norman

[sirsnorklingtayo]

Hi friend,

I've been in that kind of situation before and I used VB6 too, I developed a computer program that will keep all the SMS to my database and reply back with some information.

Ok here is the answer, before i tried that using chr(13) because this is the equivalent for the new line but unfortunately i dont know why this chr(13) is not working in MSCOM, but the only thing left is the constant value of VBCRLF you can use this as a substitute in chr(13)

Inshort

chr(13) = VBCRLF

and dont forget to send +++ it means that you will set the GSM in Command mode. Some1 already post this one, you better be careful in sending AT Command always keep in mind that before sending another batch of command you need to wait just for a second or 2, just use Sleep function in VB6.

Actually, after I solved that problem reagrading GSM and MSCOMM I realized that ANSI C is the much better language to use beacuse it is very easy to communicate with Devices like GSM. I am just telling you this because I experienced that before, but it will work fine in VB6 with MSCOMM


Norman

EXAMPLE:

Option Explicit
Private Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)
 
 
Private Sub Command1_Click()
Dim strSMS As String
'set contact number
'buffer you message here
strSMS = "Hello World!"
'Before sending command
MSComm1.Output = "+++" & vbCrLf
'wait a second
Sleep 1
'send at commands
MSComm1.Output = "AT+CMGS=" & Chr(34) & "+351nnnnnnnnn" & Chr(34) & vbCrLf
 
'There are some GSM modems that after sending "AT+CMGS"
'it will response before buffering the message
 
'Ex.
' step 1: MSComm1.Output = "AT+CMGS=" & Chr(34) & "+351nnnnnnnnn" & Chr(34) & vbCrLf
' step 2: MSComm1.Input is equal to OK/ERROR
' step 3: then > insert your message
 
'In this case the GSM is allowing you to check first if the AT command is valid or not
'before buffering the message to GSM
 
'I dont know if this is your case but you can check.
 
While 1
    'wait for 1 second or 2
 
    Sleep 1  'this is depend on how fast your GSM communicate with MSCOMM
 
    'Always wait this > sign to come out, because this the signal that the GSM is ready
    'to get the Message
 
    'if MSComm1.Input = ">" send your Message to GSM
 
    'note: make it sure that no other chr(s) in MSComm1.Input except ">"
    'The last thing to remember is do not ever try to use the DOEVENTS
 
    If StrComp(Left(MSComm1.Input, 1), ">", vbBinaryCompare) = 0 Then
        MSComm1.Output = strSMS & Chr(26)
        Sleep 2
        'Before you do this pls remove the chr(26)
        If StrComp(Replace(MSComm1.Input, Chr(26), ""), "OK", vbBinaryCompare) = 0 Then
            'place your flag
            GoTo ExitWhile
        ElseIf StrComp(Replace(MSComm1.Input, Chr(26), ""), "ERROR", vbBinaryCompare) = 0 Then
            'place your flag
            GoTo ExitWhile
        Else
    End If
Wend
 
ExitWhile:
    'do your valdations here etc
    'Check your falg here if error is true or false
    Sleep 2
 
 
End Sub

[sirsnorklingtayo]

EXAMPLE:

Option Explicit
Private Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)


Private Sub Command1_Click()
Dim strSMS As String
'set contact number
'buffer you message here
strSMS = "Hello World!"
'Before sending command
MSComm1.Output = "+++" & vbCrLf
'wait a second
Sleep 1
'send at commands
MSComm1.Output = "AT+CMGS=" & Chr(34) & "+351nnnnnnnnn" & Chr(34) & vbCrLf

'There are some GSM modems that after sending "AT+CMGS"
'it will response before buffering the message

'Ex.
' step 1: MSComm1.Output = "AT+CMGS=" & Chr(34) & "+351nnnnnnnnn" & Chr(34) & vbCrLf
' step 2: MSComm1.Input is equal to OK/ERROR
' step 3: then > insert your message

'In this case the GSM is allowing you to check first if the AT command is valid or not
'before buffering the message to GSM

'I dont know if this is your case but you can check.

While 1
'wait for 1 second or 2

Sleep 1 'this is depend on how fast your GSM communicate with MSCOMM

'Always wait this > sign to come out, because this the signal that the GSM is ready
'to get the Message

'if MSComm1.Input = ">" send your Message to GSM

'note: make it sure that no other chr(s) in MSComm1.Input except ">"
'The last thing to remember is do not ever try to use the DOEVENTS

If StrComp(Left(MSComm1.Input, 1), ">", vbBinaryCompare) = 0 Then
MSComm1.Output = strSMS & Chr(26)
Sleep 2
'Before you do this pls remove the chr(26)
If StrComp(Replace(MSComm1.Input, Chr(26), ""), "OK", vbBinaryCompare) = 0 Then
'place your flag
GoTo ExitWhile
ElseIf StrComp(Replace(MSComm1.Input, Chr(26), ""), "ERROR", vbBinaryCompare) = 0 Then
'place your flag
GoTo ExitWhile
Else
End If
Wend

ExitWhile:
'do your valdations here etc
'Check your falg here if error is true or false
Sleep 2


End Sub

In addition, please always use PDU mode in reading and sending TEXT SMS Messages.

MSComm1.Output = "AT+CMGS=0"

AT+CMGF: Message Format:
Command Possible response(s) +CMGF=[<mode>] +CMGF?+CMGF: <mode> +CMGF=?+CMGF: (list of supported <mode>s)
<mode>: 0: PDU mode;
<mode>: 1: TEXT mode;


check out about PDU encryption/Decryption methods
http://www.activexperts.com/activsms/sms/pdu/

[Killer42]

[quote=sirsnorklingtayo]

...
    'wait for 1 second or 2
    Sleep 1
...

Is this a routine of your own? I don't think VB6 has a Sleep statement. Mine doesn't, anyway.

[sirsnorklingtayo]

[quote=Killer42]

...
    'wait for 1 second or 2
    Sleep 1
...

Is this a routine of your own? I don't think VB6 has a Sleep statement. Mine doesn't, anyway.

Nop, SLEEP is an WIN32 API function it acts like a delay() function in ANSI C

Here is the declaration:

'You can place this in Form, Module Class etc but indicate the declration scope
'like Global,Public,Private
 
Private Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)
 
'to use this
 
Private Sub StopForAWhile(byval milliseconds as Integer)
 
  Sleep 1000 ' stop for 1 second
 
end sub

and I admit that I made a mistake instead of Sleep 1 it should be Sleep 1000

Sleep 1 = 1/1000 second stop
Sleep 1000 = 1second stop


Sorry for my mistakes

hehehe

norman

[Killer42]

Nop, SLEEP is an WIN32 API function it acts like a delay() function in ANSI C

Ah! Thanks for the reminder. I think I used it, years ago.

[willakawill]

In the interests of clarity for those scouring these pages for tidbits, perhaps you mean:

Private Sub StopForAWhile(byval milliseconds as Integer)
 
Sleep milliseconds ' stop for (milliseconds/1000) seconds
 
end sub

This is also a useful way to call sleep:

Private Sub WaitSec(ByVal secs as Integer)
 
Sleep secs * 1000 ' stop for secs seconds
 
end sub

[UmDois]

There was an error ("+) in the text i posted, but that was not the reason for my problem with GSM modem in VB6.

I found the solution: two more commands BEFORE the real string:

MSComm.Output = ""
MSComm.OutputBufferSize = 0
MSComm.Output = "the real string tou want to send"

And it works.

[Killer42]

Private Sub WaitSec(ByVal secs as Integer)
  Sleep secs * 1000 ' stop for secs seconds
end sub

In a case like this I recommend using Single rather than Integer for the number of seconds. It allows finer control, for example pausing for 1½ seconds.

[sirsnorklingtayo]

Congrats to all, I think our efforts paid up. The problem has been solved he he he.
So, good luck with your GSM Modem Project and thanks for the Information about the 2 lines of codes. I don't know about those codes and I never tried that before, but the more important is your program is now up and running. Happy coding with AT Commands

And about SLEEP sleep function, ya you are right SLEEP secs * 1000 I think this is the most clear example than mine.

Sleep secs * 1000 'seconds to wait

And I made a mistake again ha ha ha, Instead of using INTEGER for the Variable (millimseconds) use LONG data type in my last example.


Norman