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Communications

MAIN FUNCTIONS:
Open(PortName, Setup)
Close()
WriteString(Data)
ReadString(Length)
WriteByte(Data)
ReadByte()
SetTimeOut(Time)
SetTimeOuts(BaseTime, Multiplier)        New
SetHandshaking(HSMethod)
WriteData(Data, Length)
ReadData(Length)
 

ADDITIONAL FUNCTIONS:
BytesRead()
ListPorts(Index, Type)
NumberRetries(Retries)
DataBuffer
Mode
PortName
NumBytesRead
NumBytesWritten
GetPortHandle()
SetBufferSize(InSize, OutSize)
Sleep()
Wait()                New
OpenEx()         New
CancelIO()       New
 

Status

ParallelStatus
SerialStatus
NumCharsInQue
NumCharsOutQue

IOStatusEvent(StatusType, IOStatus)
IOCompleteEvent(JobType, JobId, JobResult)
IOQueueEvent(NumCharsInputQue, NumCharsOutputQue)      New
IOPeriodicEvent()New

StatusEventInterval
PeriodicEventEnabledNew
 

Parallel Specific

InitPrinter()New
Out()
In()
DeviceControl()New
 

Serial Specific

SerialPortSetupDialog()New
SerialSetPortDefaults() New
SerialGetPortDefaults() New
SerialBreak()               New
 

Serial Specific (Advanced)

SerialCTSFlow(Value)
SerialDSRFlow(Value)
SerialDTRControl(long Value)
SerialDSRSensitivity(Value)
SerialTxContinueOnXoff(Value)
SerialOutX(Value)
SerialInX(Value)
SerialErrorReplacment(Value)
SerialNullStripping(Value)
SerialRTSControl(Value)
SerialXonLimit(Value)
SerialXoffLimit(Value)
SerialXonCharacter(Value)
SerialXoffCharacter(Value)
SerialErrorCharacter(Value)
SerialEndCharacter(Value)

Remarks
Opens a port for doing input and output.

Returns
1 if successful and 0 if the function fails.
2 if successful but the port setup fails can happen when another app is using the port.
 

Example
Result = IO1.Open("LPT1:", "") 'Open a parallel Port.
Result = IO1.Open("COM2:", "baud=9600 parity=N data=8 stop=1") 'Open a serial Port.
Result = IO1.Open("\\.\digi1", "baud=9600 parity=N data=8 stop=1") 'Open a serial Port.
Result = IO1.Open("\\.\COM22", "baud=9600 parity=N data=8 stop=1") 'Open a serial Port.

NOTE: On Win NT Open() can fail if another device/driver is setup to use the port you are trying to open. Remove all devices/drivers setup to use this port, including printer drivers.
 

Remarks
Closes an open port.

Returns
1 if successful and 0 if the function fails.

Example
Result = IO1.Close()
 
 
 
 

Remarks
Writes a string to the previously opened port. For binary data use the WriteData function. If the function fails, you may need to increase the timeout value via SetTimeOuts.

Returns
1 if successful and a 0 if the function fails.

Example
Result = IO1.WriteString("Hello World" + Chr(13) + Chr(10)) 'Sends "Hello World" to a printer or other device.
 
 
 

Remarks
Reads characters from an opened port and returns them as a string. For binary data use the function ReadData. When reading data from a parallel port, this function uses the RS1284 protocol for reading data from the parallel port. If the function fails, you may need to increase the timeout value via SetTimeOuts.

Example
String = IO1.ReadString(30) 'Reads data from a port. Typically a request for data precedes this command.
 
 
 
 

Remarks
Writes a byte/character to the previously opened port. If the function fails, you may need to increase the timeout value via SetTimeOuts.

Returns
1 if successful and a 0 if the function fails.

Example
Result = IO1.WriteByte(Chr(10)) 'Sends Line feed to a printer or other device.
 
 
 

Remarks
Reads a byte/character from an opened port. When reading data from a parallel port, this function uses the RS1284 protocol for reading data from the parallel port. This function returns the byte data in an integer. Some environments my sign extend this value. You may wish to do a bitwise AND with the value read from this function and a hex FF to restore it to an unsigned value.

Returns
The byte/character.

Example
Result = IO1.ReadByte() 'Reads 1 data byte from a port. Typically a request for data precedes this command.
  OR
Result = IO1.ReadByte() And &Hff 'restores to unsigned byte
 
 
 
 

Remarks
Sets the time out factor for a port. The write/read operation will be tried until the time is expired. If the timeout expires, the function will return an error (0) result.

Returns
1 if successful and a 0 if the function fails.

Example
Result = IO1.SetTimeOut(20) 'Sets timeout factor, how long a request is tried before an error is returned.
 

Remarks
Sets the time out factor for a port. The write/read operation will be tried until the time is expired. If the timeout expires, the function will return an error (0) result.  For Reading a port the timeout will be: BaseTime + (number of characters to read) x Multiplier .For writing to a port the time out will be: BaseTime + (number of characters to write) x Multiplier.
 

Returns
1 if successful and a 0 if the function fails.

Example
Result = IO1.SetTimeOut(200, 20) 'Sets timeout factor, how long a request is tried before an error is returned.
 
 
 
 
 

Remarks
Sets the type of handshaking to be used with this port, the device must be configured to use the same type of handshaking protocol.  Calling this function will reset the baud rate, parity, and stop bits to the values passed into the Open() function.  This function should be called before the "Advanced Serial Communications" functions.  SetHandshaking() will cancel the "Advanced Serial Communications" functions settings.

Returns
1 if successful and a 0 if the function fails.

Example
Result = IO1.SetHandshaking(2) 'Serial ports Only. 0 = None, 1 = Xon/Xoff, 2 = Hardware
 
 
 
 
 
 

Remarks
Writes data to the previously opened port. If the function fails, you may need to increase the timeout value via SetTimeOuts.

Returns
The length of data written if successful and a 0 if the function fails.

Example
Result = IO1.WriteData("String1" + Chr(00) + "String2" + Chr(00) + "String3" + Chr(00) + Chr(00)) 'Sends 3 null terminated strings to the port, with the total data being double null terminated.
 
 
 

Remarks
Reads bytes from an opened port and returns them in a string. The data can have null bytes. Even thought this function will return a string with embedded nulls other functions that operate on strings may not be null friendly. When reading data from a parallel port, this function uses the RS1284 protocol for reading data from the parallel port.

Returns
Binary data in a string.

Example
String = IO1.ReadData(30) 'Reads data from a port. Typically a request for data precedes this command.
 
 
 
 

Remarks
Return the number of bytes previously read from the port. This value corresponds to the last read function done on this port. For use with the ReadData() function.

Returns
The number of bytes previously read function called.

Example
String = IO1.ReadData(30) 'Reads data from a port.
NumBytes = IO1.BytesRead() 'returns number of bytes read.
 
 
 
 
 

Remarks
Type is 1 for COM ports, 2 for LPT ports and, 4 for all ports. Note you can OR these values together to get a combination.

Returns
Returns the ports availble on the machine for the given index.

Example
For i = 0 To 10
Label2.Caption = Label2.Caption + IO1.ListPorts(i, 1) + " "
Next i
 
 
 
 

Remarks
Default is 1 retry.

Returns
Returns 1.

Example
Result = IO1.NumberRetries(1)
 
 
 
 

Remarks
This function returns the handle of the currently opened port. This function is provided to allow calls to the Windows API directly.

Returns
The handle of the currently opened port.

Example
Result = IO1.GetPortHandle()
 

Remarks
This function sets the size of the input and output buffer associated with the opened port. Caution should be taken when using this function, some hardware running Windows 95 can function incorrectly when overriding the default buffer size with a serial port.

Returns
0 if the function fails.

Example
Result = IO1.SetbufferSize(InSize, OutSize)
 
 

Remarks
This function delays for the number of milliseconds specified. This function is provided to allow for custom timing of signals on the ports.
 

Returns
None.

Example
IO1.Sleep(500) ‘delay for 500ms (½ second).
 
 

Remarks
This function delays for the number of milliseconds specified. This function differs from Sleep() in that it will yield the current thread to allow the application to process user input.  This yielding lets the application respond to user input instead of appearing to "hang" during a long delay.  Because this functions yields to other tasks, it may delay for longer than the time specified.
 

Returns
None.

Example
IO1.Wait(500) ‘delay for at least 500ms (½ second).
 
 

Remarks
Opens a port for doing input and output.

Example
Result = IO1.Open("LPT1:", "", OPEN_MODE_SHARE, 0) 'Open a parallel Port. In shared mode.

NOTE: On Win NT Open() can fail if another device/driver is setup to use the port you are trying to open. Remove all devices/drivers setup to use this port, including printer drivers.

Example:
If (IOStatus And PARALLEL_SELECTED) Then
NewText = NewText + "Selected. "
Else
NewText = NewText + "Not Selected. "
End If
 

Example:
If (IOStatus And SERIAL_RXEMPTY) Then
NewText = NewText + "RX Buffer Empty, "
else
NewText = NewText + "RX Buffer Not Empty, "
End If

STATUS_TYPE_PARALLEL 1

STATUS_TYPE_SERIAL 2
IOStatus. Specifies the status pertaining to the open port. See the definition of SerialStatusand ParallelStatusfor the value of this parameter.

Remarks

This event is fired whenever a status change is detected on the port. How often status is checked and events are generated is set by StatusEventInterval (default of 250 milliseconds).

BKJOB_WRITE 3

BKJOB_READ 4

JobId. Specifies the Id of the job submitted for background processing.
JobResult. Specifies the result of the job submitted for background processing.

Remarks
This event is fired whenever a background job is finished.  If a read operation is completed, DataBuffer will contain the result of the read operation.
 
 

Remarks
This event is fired whenever the number of character in either the input or output queue has changed.  This event is provided to allow the application designer to monitor the communications activity.

Example:

If (NumCharsInputQue > 0) Then

Remarks
This event is fired whenever the StatusEventInterval has expired.  This event is provided to allow the applications designer to add custom communications monitoring on a periodic basis.  This event is enable by setting the property PeriodicEventEnabled to TRUE (1).
 
 

Remarks
Because this is used to write a data byte directly to the parallel port hardware, do not call the Open() or Close() functions when using the Out() function..  See below for the address of standard parallel ports.

Port addresses:

          LPT1: 378 Hex(Data), 379 Hex(Status), 37A Hex(Control)

          LPT2: 278 Hex(Data), 279 Hex(Status), 27A Hex(Control)

          LPT3: 3BC Hex(Data), 3BD Hex(Status), 3BE Hex(Control)
 

Remarks
Because this is used to read a data byte directly from the parallel port hardware, do not call the Open() or Close() functions when using the In() function.  See below for the address of standard parallel ports.

Returns
The data byte of the addressed port register.

Port addresses:

          LPT1: 378 Hex(Data), 379 Hex(Status), 37A Hex(Control)

          LPT2: 278 Hex(Data), 279 Hex(Status), 27A Hex(Control)

          LPT3: 3BC Hex(Data), 3BD Hex(Status), 3BE Hex(Control)
 

Remarks
This method displays the serial port setup dialog and allows a user to adjust the port settings.  After the dialog is dismissed by clicking on the "OK" button, the new settings are applied to the currently open port. If no port is open, the settings are saved in the I/O object and can be stored by calling the SerialSetPortDefaults() function.  If the PortName is blank (i.e. ""), the dialog will use the port name of the most recently opened port.
 

Returns
1 for success
0 for fail or cancel button was clicked.

Example

IO1.SerialGetPortDefaults (PortName)     'Get port settings
Result = IO1.SerialPortSetupDialog(PortName)     'Allow user to setup port
If Result = 1 Then
    Result = IO1.SerialSetPortDefaults(PortName, "", -1)       'Save the settings
End If

Remarks
This method allows setting of the default settings of a serial port.  The default settings for a port are maintained/save by the operating system.  If Setup is blank (i.e. ""), this function will use the settings of the last opened port or the settings entered via the SerialPortSetupDialog() function.  If the HSMode is -1, this function will use the settings of the last opened port or the settings entered via the SerialPortSetupDialog() function..  If the PortName is blank (i.e. ""), this function will use the port name of the most recently opened port.  This function will also change/set the settings for the currently opened port (if one is opened).
 

Returns
1 for success or 0 for fail.

Remarks
This method allows retrieval of the default settings of a serial port.  The default setting for a port are maintained/save by the operating system.  If the PortName is blank (i.e. ""), this function will use the port name of the most recently opened port.  This function should be called after the port is opened, as opening of the port will overwrite the setting retrieved by calling this function.

Returns
1 for success or 0 for fail.

Remarks
This method allows the open serial port to be put into a break condition.

Returns
1 for success or 0 for fail.

Remarks
Specifies whether the CTS (clear-to-send) signal is monitored for output flow control. If it is 1 and CTS is low, output is suspended until CTS is high again. The CTS signal is under control of the device (usually a modem/printer), the host simply monitors the status of this signal, the host does not change it. This function should be called before the port is opened.

Returns
1 if successful or 0 if failed.

Example
Result = IO1.SerialCTSFlow(1)
...
Result = IO1.Open("COM2:", "baud=9600 parity=N data=8 stop=1") 'Open a serial Port.
 
 
 

Remarks
Specifies whether the DSR (data-set-ready) signal is monitored for output flow control. If this member is 1 and DSR is low, output is suspended until DSR is high again. This signal is under the control of the attached device; the host(PC) only monitors this signal. This function should be called before the port is opened.

Returns
1 if successful or 0 if failed.

Example
Result = IO1.SerialDSRFlow(1)
...
Result = IO1.Open("COM2:", "baud=9600 parity=N data=8 stop=1") 'Open a serial Port.
 

Remarks
If 0 then the DTR line is lowered when the device is opened.
If 1 then the DTR line is raised when the device is opened.
If set to 2 enables DTR flow-control handshaking.
After the port is opened:
If called with a value of 5 sets DTR high. Only allowed if SerialDTRControl was set to 1 0r 0 before the port was opened.
If called with a value of 6 sets DTR low. Only allowed if SerialDTRControl was set to 1 0r 0 before the port was opened.

Returns
1 if successful or 0 if failed.
Example
Result = IO1.SerialDTRControl(0)
...
Result = IO1.Open("COM2:", "baud=9600 parity=N data=8 stop=1") 'Open a serial Port.
...
Result = IO1.SerialDTRControl(5)
 
 

Remarks
Specifies whether the communications driver is sensitive to the state of the DSR signal. If this is set to a 1, the driver ignores any bytes received, unless the DSR modem input line is high.

Returns
1 if successful or 0 if failed.

Example
Result = IO1.SerialDSRSensitivity(1)
...
Result = IO1.Open("COM2:", "baud=9600 parity=N data=8 stop=1") 'Open a serial Port.
 

SerialTxContinueOnXoff(Value)
Parameters
Value 1 or 0. Controls Xon/Xoff behavior. Undetermined results if set to other than 1 or 0.

Remarks
Specifies whether transmission stops when the input buffer is full and the driver has transmitted the XOFF character. If this is set to a 1, transmission continues after the XOFF character has been sent. If this is set to a 0, transmission does not continue until the input buffer is within SerialXonLim bytes of being empty and the driver has transmitted the XON character.

Returns
1 if successful or 0 if failed.

Example
Result = IO1.SerialTxContinueOnXoff(1)
...
Result = IO1.Open("COM2:", "baud=9600 parity=N data=8 stop=1") 'Open a serial Port.
 
 

Remarks
Specifies whether XON/XOFF flow control is used during transmission. If this member is a 1, transmission stops when the XOFF character is received and starts again when the XON character is received.

Returns
1 if successful or 0 if failed.

Example
Result = IO1.SerialOutX(1)
...
Result = IO1.Open("COM2:", "baud=9600 parity=N data=8 stop=1") 'Open a serial Port.
 
 
 
 

Remarks
Specifies whether XON/XOFF flow control is used during reception. If this is set to a 1, the XOFF character is sent when the input buffer comes within a preset limit of bytes of being full (see SerialXonLimit and SerialXoffLimit), and the XON character is sent when the input buffer comes within a preset limit of bytes of being empty.

Returns
1 if successful or 0 if failed.

Example
Result = IO1.SerialInX(1)
...
Result = IO1.Open("COM2:", "baud=9600 parity=N data=8 stop=1") 'Open a serial Port.
 
 
 

Remarks
Specifies whether bytes received with parity errors are replaced with the character specified by the SerialErrorCharacter member function. If this is set to a 1 and the Parity is set to a 1, replacement occurs.

Returns
1 if successful or 0 if failed.

Example
Result = IO1.SerialErrorReplacment(1)
...
Result = IO1.Open("COM2:", "baud=9600 parity=N data=8 stop=1") 'Open a serial Port.
 
 
 

Remarks
Specifies whether null bytes are discarded. If this is set to 1, null bytes are discarded when received.

Returns
1 if successful or 0 if failed.

Example
Result = IO1.SerialNullStripping(1)
...
Result = IO1.Open("COM2:", "baud=9600 parity=N data=8 stop=1") 'Open a serial Port.
 
 
 
 
 

Remarks
If 0 then the RTS line is lowered when the device is opened.
If 1 then the RTS line is raised when the device is opened.
If set to 2 enables RTS flow-control handshaking. The driver raises the RTS line, enabling the attached device to send (when the input buffer has enough room to receive data). The driver lowers the RTS line, preventing the attached device from sending (when the input buffer does not have enough room to receive data).
If set to 3 specifies that the RTS line will be high if bytes are available for transmission. After all buffered bytes have been sent, the RTS line will be low. (Not supported on Win95)
After the port is opened:
If called with a value of 5 sets RTS high. Only allowed if SerialRTSControl was set to 1 0r 0 before the port was opened.
If called with a value of 6 sets RTS low. Only allowed if SerialRTSControl was set to 1 0r 0 before the port was opened.

Returns
1 if successful or 0 if failed.

Example
Result = IO1.SerialRTSControl(0)
...
Result = IO1.Open("COM2:", "baud=9600 parity=N data=8 stop=1") 'Open a serial Port.
...
Result = IO1.SerialRTSControl(5)
 
 
 
 
 

Remarks
Specifies the minimum number of bytes allowed in the input buffer before the XON character is sent.

Returns
1 if successful or 0 if failed.

Example
Result = IO1.SerialXonLimit(256)
...
Result = IO1.Open("COM2:", "baud=9600 parity=N data=8 stop=1") 'Open a serial Port.
 
 
 
 

Remarks
Specifies the maximum number of bytes allowed in the input buffer before the XOFF character is sent.

Returns
1 if successful or 0 if failed.

Example
Result = IO1.SerialXoffLimit(100)
...
Result = IO1.Open("COM2:", "baud=9600 parity=N data=8 stop=1") 'Open a serial Port.
 
 
 
 
 

Remarks
Specifies the Xon character.

Returns
1 if successful or 0 if failed.

Example
Result = IO1.SerialXonCharacter(17)
...
Result = IO1.Open("COM2:", "baud=9600 parity=N data=8 stop=1") 'Open a serial Port.
 
 
 

Remarks
Specifies the Xoff character.

Returns
1 if successful or 0 if failed.

Example
Result = IO1.SerialXoffCharacter(19)
...
Result = IO1.Open("COM2:", "baud=9600 parity=N data=8 stop=1") 'Open a serial Port.
 
 
 
 

Remarks
Specifies the Error character, the character used to replace bytes received with a parity error.

Returns
1 if successful or 0 if failed.

Example
Result = IO1.SerialErrorCharacter('?')
...
Result = IO1.Open("COM2:", "baud=9600 parity=N data=8 stop=1") 'Open a serial Port.
 
 
 

Remarks
Specifies the End character, the character used to signal the end of data.

Returns
1 if successful or 0 if failed.

Example
Result = IO1.SerialEndCharacter(FF)
...
Result = IO1.Open("COM2:", "baud=9600 parity=N data=8 stop=1") 'Open a serial Port.