How to read response from printer in language monitor

Question

How to read response from printer in language monitor

Terry Chou 1

I'm developing a printer driver(unidrv), and writing a language monitor to get some information from my printer.
My language monitor is modified from pjlmon.dll example. It get the response correctly from printer with USB port. However, It doesn't work properly with TCP/IP and COM port.

With COM port, I've used sniffer software. I found when I call "fn.pfnWritePort" port monitor function, it will close COM port finally. This cause I can't get the response by "fn.pfnReadPort" port monitor function.

With TCP/IP, there are two cases.

when I call WriteCommand() and ReadCommand() function in PJLMonGetPrinterDataFromPort() language monitor function, I get error code 6 after "fn.pfnWritePort" port monitor function and error code 50 after "fn.pfnReadPort" port monitor function.
when I call WriteCommand() and ReadCommand() function in PJLMonStartDocPort() language monitor function, I can successfully call WriteCommand() and see the packets in WireShark, but still get error code 50 after "fn.pfnReadPort" port monitor function.

How should I read the response from printer in my language monitor via TCP/IP and COM?

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Answer 1

Limitless Technology 44,766

Hello there,

If you specifically need to get information from TCP/IP you might need to look into transceive (Xcv) interface.

The article below describes the transceive (Xcv) interface for the standard TCP/IP port monitor (TCPMON). This interface, which is implemented using XcvData and XcvDataPort function calls, enables those using it to configure a TCP/IP printer port or to obtain information about a TCP/IP printer port configuration. The Xcv interface described in this section is specific to TCP/IP ports. Other Xcv interfaces might be available for other port types.

More info here https://learn.microsoft.com/en-us/windows-hardware/drivers/print/tcpmon-xcv-interface

Microsoft provides a language monitor, Pjlmon.dll, which supports printer job language (PJL), and provides bidirectional communication for PJL printers.

Language monitors https://learn.microsoft.com/en-us/windows-hardware/drivers/print/language-monitors

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Terry Chou 1

Hello,

Thanks for the response. I've looked the article you provided. Unfortunately, it seems that there is no way to send and receive data from the printer.

XcvData can do something with specific command as the parameter. The supported commands for tcpmon are listed in tcpmon-xcv-commands. From the article, no command supports sending and receiving data.

Like example below, it shows how to get TCP/IP port configuration through XcvData with "GetConfigInfo" command.

PRINTER_DEFAULTS Defaults1 = { NULL, NULL, SERVER_ACCESS_ADMINISTER };  
HANDLE hXcv = NULL;  
CString strPortName;  
strPortName = _T(",XcvPort 192.168.102.8");  
if (OpenPrinter((LPTSTR)(LPCTSTR)strPortName, &hXcv, &Defaults1))  
{  
	CONFIG_INFO_DATA_1 configInfoData1;  
	memset(&configInfoData1, 0, sizeof(configInfoData1));  
	configInfoData1.dwVersion = 1;  

	PORT_DATA_1 portData1;  
	memset(&portData1, 0, sizeof(portData1));  
	portData1.cbSize = sizeof(portData1);  

	DWORD dwStatus = 0;  
	DWORD dwNeeded = 0;  

	XcvData(hXcv, L"GetConfigInfo", (PBYTE)&configInfoData1,  
		sizeof(configInfoData1), (PBYTE)&portData1, sizeof(portData1), &dwNeeded, &dwStatus);  

	ClosePrinter(hXcv);  
}

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