Using MSComm for serial communication

Submitted on: 1/3/2015 5:43:00 AM
By: Paul R. Richards (from psc cd)  
Level: Beginner
User Rating: By 6 Users
Compatibility: Microsoft Visual C++
Views: 1944
     How to use Microsofts Communication Control MSCOMM


If you would like to use the Microsoft 
<--[if gte mso 9]>
 Paul Richards

If you would like to use the Microsoft

Communications Control, here are the steps in VC:


1) Create a dialog in VC++


2) Project->Add to Project->Components and Controls


3) Find "Microsoft Communications Control" click insert


4) Drag the now visible phone icon onto your dialog


5) Select phone icon and hit cntrl-w for class wizard


6) Click on Member Variables and click on IDC_MSCOMM1


7) Add a member variable name (m_Comm) for the control


8) You can now open the serial port (1) using this code:

m_Comm.SetCommPort (1); // Com port 1

m_Comm.SetSettings ("38400,e,8,1");

m_Comm.SetInputMode (1); // Binary mode

m_Comm.SetPortOpen (TRUE); // Open it

// Note: you may want to flush the buffer here, by

// reading and throwing away the data

// m_Comm.GetInput();


9) To send data use this code:

CByteArray btArray;

btArray.Add (0x00); // Byte 1

btArray.Add (0x13); // Byte 2

COleVariant var(btArray);

m_Comm.SetOutput(var); // Send the data.


10) To read data use this code:

COleVariant myVar;

int hr;

long lLen = 0;

BYTE *pAccess;

char buffer[255];


myVar.Attach (m_Comm.GetInput());

// Get the length

hr = SafeArrayGetUBound (myVar.parray, 1, &lLen);

if (hr == S_OK)


lLen++; // upper bound is zero based index

// lock array so you can access it.

hr = SafeArrayAccess (myVar.parray,(void**)&pAccess);

if (hr == S_OK)


// Make a copy of the data

// Note: Need to check that lLen is < buffer length

// so you don't overrun the buffer.

for (int i 0; i < lLen; i++)

buffer[i] = pAccess[i];


// unlock the data

SafeArrayUnaccessData (myVar.parray);



// COleVariant cleans itself up

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