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="+351nn nnnnnnn" <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) & "+ "+351nnnnnn nnn" & 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="+351nn nnnnnnn" <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) & "+ "+351nnnnnn nnn" & 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) & "+ "+351nnnnnn nnn" & chr(34) & chr(13)
  seems to have quotes in the wrong places. It probably should have been
  MSComm.Output = "AT+CMGS=" & chr(34) & "+351nnnnnn nnn" & 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]"+ "+351nnnnnn nnn" [/PHP]

You have "+ twice.

[iburyak]

Try this:

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

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

[willakawill]

Try this:

MSComm.Output = "AT+CMGS=""+351 nnnnnnnnn""" & 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="+351nn nnnnnnn" <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) & "+ "+351nnnnnn nnn" & 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