Find Modem

[Gösta H. Lovgren-2]

Searching for code to find Comport with a modem attached, all that I found (plenty hits) were more than either I wanted to fool with, or more than I understood. So here's a simple version I came up with. Probably lots of bad stuff is gonna happen (BSOD's, GPF's, ...) but it works on my machine at least (so far).

'

'Find Modem.bas  - 'XP SP3  - PBWin 8.03
#Compile Exe  
#Include "WIN32API.INC"
 
Sub Find_Modem_Comport
   Local ctr&, byts&, ComPort$, ncomm&, prts$, n$
   ncomm = FreeFile
   ErrClear
   For ctr = 0 To 9             
     COMPORT$ = "COM" & Using$("# ", ctr)
 
    Comm Open COMPORT$ As #nComm
    Sleep 100 'JIC it needs the time to open 
 
    If Err Then 'no modem attached here
       Close ncomm  'JIC
       ErrClear     'set to 0 for next try
      Else                                
       'Got a modem maybe
       Comm Set #nComm, Baud     = 115200   ' 9600 baud
       Comm Set #nComm, Byte     = 8        ' 8 bits
       Comm Set #nComm, Parity   =  %False   ' No parity
       Comm Set #nComm, Stop     = 0        ' 1 stop bit
       Comm Set #nComm, TxBuffer = 4096     ' 4k transmit buffer
       Comm Set #nComm, RxBuffer = 4096     ' 4k receive buffer
 
      'n$ = "ATDT 1234567" & $CrLf '<< Hear dial tone and number dialed but returns nothing
      'n$ = "+++"    '<< returns nothing
      n$ = "AT" & $CrLf  'returns OK
      Comm Send #nComm, n$  
      Sleep 10 'wait for reply
                'nothing returns regardless of how Long 
                'except For "AT" which return "OK"
 
      byts = Comm(#nComm, RxQue)
      Comm Recv #nComm, byts, n$
      Comm Send #nComm, "ATH0" & $CrLf 'hang up JIC it dials
 
       If byts > 0 Then  'Valid modem available
         ? "Received " & n$,, COMPORT$ & " is GOOD "  
       End If
    End If                         
'
    Close ncomm
   Next ctr        
   Close
End Sub
 
 
Function PBMain
Call Find_Modem_Comport
End Function
'

[Erich Schulman]

There are free sources at http://www.codeproject.com/KB/system/DevMgr.aspx and http://69.10.233.10/KB/system/SimpleSetup.aspx which might be helpful. Once you find the modem(s), check that it is ready for use (or there might be a method you can call to have Windows query the modem for you).

If this project is just for yourself or a single client/employer, you have the advantage that you can check ahead of time on what serial devices are in use. But if this is for the general public, don't send AT commands to every serial device. There are lots of serial devices that are not modems, and you can't predict what would happen when someone runs your program.

[Gösta H. Lovgren-2]

There are free sources at http://www.codeproject.com/KB/system/DevMgr.aspx and http://69.10.233.10/KB/system/SimpleSetup.aspx which might be helpful. Once you find the modem(s), check that it is ready for use (or there might be a method you can call to have Windows query the modem for you).

Thanks the links, Erich. They look way more than I want to, or can, handle right now though.

If this project is just for yourself or a single client/employer, you have the advantage that you can check ahead of time on what serial devices are in use. But if this is for the general public, don't send AT commands to every serial device. There are lots of serial devices that are not modems, and you can't predict what would happen when someone runs your program.

Excellent point. While it won't have a wide distribution (probably just family) it's back to the drawing boards for me. Thanks your reply.

====================================================
"I'm not a member of any organized political party,
I'm a Democrat!"
Will Rogers (1879-1935)
====================================================

[Gösta H. Lovgren-2]

After a further search, I found this:

It won't work with a For/Next loop though.

I'm wondering if it would have the same "conflict" as Erich pointed out with my code?
'

'http://www.powerbasic.com/support/pbforums/showthread.php?t=6468&highlight=modem+detection
'by Peter Lameijn
'==================================================================================================
' Modem detection example. PST_xxx equates are in Winbase.h
'==================================================================================================
#Include "win32api.inc"
%PST_MODEM = &h00000006&
Function PBMain () As Long
Local lRet&,lComm&,lCommProp As CommProp
Local Comport$, ctr&, p_ptr&
 
 '<<< This commented section works fine.
'  lComm& = CreateFile("COM1",%GENERIC_READ Or %GENERIC_WRITE,0,ByVal %Null,%OPEN_EXISTING,%FILE_FLAG_OVERLAPPED,ByVal %Null)
'  If lRet = %INVALID_HANDLE_VALUE Then Exit Function
'  lRet = GetCommProperties(lComm&,lCommProp)
'  If lCommProp.dwProvSubType = %PST_MODEM Then ? "Modem on Com 2"
'  CloseHandle lComm&
'
'  lComm& = CreateFile("COM2",%GENERIC_READ Or %GENERIC_WRITE,0,ByVal %Null,%OPEN_EXISTING,%FILE_FLAG_OVERLAPPED,ByVal %Null)
'  If lRet = %INVALID_HANDLE_VALUE Then Exit Function
'  lRet = GetCommProperties(lComm&,lCommProp)
'  If lCommProp.dwProvSubType = %PST_MODEM Then ? "Modem on Com 2"
'  CloseHandle lComm&
'
'  lComm& = CreateFile("COM3",%GENERIC_READ Or %GENERIC_WRITE,0,ByVal %Null,%OPEN_EXISTING,%FILE_FLAG_OVERLAPPED,ByVal %Null)
'  If lRet = %INVALID_HANDLE_VALUE Then Exit Function
'  lRet = GetCommProperties(lComm&,lCommProp)
'  If lCommProp.dwProvSubType = %PST_MODEM Then ? "Modem on Com 3"
'  CloseHandle lComm&
'
'  lComm& = CreateFile("COM4",%GENERIC_READ Or %GENERIC_WRITE,0,ByVal %Null,%OPEN_EXISTING,%FILE_FLAG_OVERLAPPED,ByVal %Null)
'  If lRet = %INVALID_HANDLE_VALUE Then Exit Function
'  lRet = GetCommProperties(lComm&,lCommProp)
'  If lCommProp.dwProvSubType = %PST_MODEM Then ? "Modem on Com 4"
'  CloseHandle lComm&
 
 
'<<< However this does not work,  it gives a "Parameter Mismatch error            
 For ctr = 0 To 9
   'Doesn't work
'  Comport$ = Left$("COM" & Using$("#", ctr), 4) & $Nul
'  lComm& = CreateFile(Comport$, %GENERIC_READ Or %GENERIC_WRITE,0,ByVal %Null,%OPEN_EXISTING,%FILE_FLAG_OVERLAPPED,ByVal %Null)
 
   'Nor does this
  p_Ptr = StrPtr(Comport$) 'didn't work either
  lComm& = CreateFile(p_Ptr, %GENERIC_READ Or %GENERIC_WRITE,0,ByVal %Null,%
 
OPEN_EXISTING,%FILE_FLAG_OVERLAPPED,ByVal %Null)
  If lRet = %INVALID_HANDLE_VALUE Then Exit Function
  lRet = GetCommProperties(lComm&,lCommProp)
  If lCommProp.dwProvSubType = %PST_MODEM Then ? "Modem on " & Comport$
  CloseHandle lComm&
 
 Next ctr                     
 
 
  ? "Done",,FuncName$
End Function
'

Note there are other methods on there as well.

[Cliff Nichols]

Just to spurn on debate

      byts = Comm(#nComm, RxQue)
      Comm Recv #nComm, byts, n$
      Comm Send #nComm, "ATH0" & $CrLf 'hang up JIC it dials

I have YET to see anything reply to a modem call (unless just echoing what was sent to it) unless something was attached.

Now just WHAT is attached that is a matter of what the core idea of the application is.....

[Gösta H. Lovgren-2]

Just to spurn on debate

      byts = Comm(#nComm, RxQue)
      Comm Recv #nComm, byts, n$
      Comm Send #nComm, "ATH0" & $CrLf 'hang up JIC it dials

I have YET to see anything reply to a modem call (unless just echoing what was sent to it) unless something was attached.

Dunno what you mean by "attached" but in this case the n$ contains "OK" received from the modem according to the MsgBox:

      If byts > 0 Then  'Valid modem available
         ? "Received " & n$,, COMPORT$ & " is GOOD "

Now just WHAT is attached that is a matter of what the core idea of the application is.....

Now THAT flies right over my head. The "core idea" in this case is to see if a modem is available on a comport. As Erich pointed out, the way I was trying was fraught with imminent peril. Peter L's solution seems the better way.

==================================
"Give me chastity and continence,
but not yet."
Saint Augustine (354-430)
==================================

[Gösta H. Lovgren-2]

Note for those following this thread, there is a cleaner version of Peter's code (updated to PBWin 8.04) version at: http://www.powerbasic.com/support/pb...018#post293018 (Post 24).

=============================
Let's have some new cliches.
Samuel Goldwyn
=============================

[Erich Schulman]

Just to spurn on debate
I have YET to see anything reply to a modem call (unless just echoing what was sent to it) unless something was attached.

And that is where the potential trouble lies.

I have a Moxa 8-port serial card because I have multiple serial devices. My PDA needs 2 (one for PPP, one for sync). I also have VHF and UHF transceivers that use serial ports. If I get a terminal node connector for them, that's another serial port. I also have an external modem, and I have a serial mouse (normally on the shelf) so if my regular mouse breaks I've got something to tide me over until I can get to the store.

Someone making a modem-oriented program would not know in advance that I have those diverse serial devices. What would each device do when getting a modem command? I have never bothered to find out, but it could be nothing or something disruptive. At least a program made for just yourself or a limited audience gives you the advantage of a chance to find out what devices are out there now and planned for the future.

[Dave Biggs]

Note for those following this thread, there is a cleaner version of Peter's code (updated to PBWin 8.04) version at: http://www.powerbasic.com/support/pb...018#post293018 (Post 24).

Peter posted another version of his code here..

http://www.powerbasic.com/support/pbforums/showthread.php?t=35506

[Cliff Nichols]

Maybe this will help List Available Serial Ports

I know I posted a more simplified listing somewhere, but could not find it in the search on my own name