Troubleshooting Print-Sharing Devices

ID: Q84491

The information in this article applies to:
  • Microsoft Windows versions 3.0, 3.0a, 3.1, 3.11

SUMMARY

Microsoft Windows supports printing in the following hardware configurations:

  • A printer connected directly to a supported LPT or COM port


  • A printer connected to a network print server on a supported network


It is possible to print using print-sharing devices or switch boxes, although this is untested and unsupported by Microsoft. This article discusses some of the problems Windows is faced with when printing through these devices.


MORE INFORMATION

There are two types of print-sharing devices:

  • Manual switch boxes


  • Electronic switch boxes


Manual Print-Sharing Devices

Manual print-sharing devices require that you manually move a switch or dial to select one printer or another. These devices are sometimes referred to as AB boxes. The main difficulty associated with manual switch boxes is that they may not pass through all the pin connections that Windows needs when it normally prints.

Electronic Print-Sharing Devices

Electronic print-sharing devices electronically poll each connected communications line (LPT ports or more commonly COM ports) for a short period of time; if no handshake is made (no response), the next port is polled. If a handshake is made, the port is monitored until no more data is being sent, then the next port is polled. The two most common problems with these devices are:
  1. They may not pass through all the pin connections that Windows needs when it normally prints.


  2. The polling rate or type of handshaking may need to be adjusted to work with Windows.


If you are having problems when attempting to print from Windows with one of these devices, try the following:

  1. Can you print from MS-DOS? If not, then contact the manufacturer of the print-sharing device. To test printing from MS-DOS:

    1. At the MS-DOS prompt, type the following:
      copy autoexec.bat lpt1
      Note: Substitute the port being used for the LPT1 entry above. This will work for all printers except PostScript printers. For PostScript printers, type the following at the MS-DOS prompt:
      copy c:\windows\system\testps.txt lpt1


    Note: Substitute the port being used for the LPT1 entry above.


  2. Disable Print Manager:

    1. Run Control Panel and choose the Printers icon.


    2. Clear the Use Print Manager box.




  3. Disable the Fast Printing Direct to Port option:

    1. Run Control Panel and choose the Printers icon.


    2. Choose the Connect button.


    3. Clear the Fast Printing Direct To Port check box.




  4. If you are on an unsupported network, and you have installed Windows for a network, you may need to disable the Print Network Jobs Directly and Update Network Display options:

    1. Run Print Manager.


    2. Choose Options and Network Settings.


    3. Clear the check boxes for Print Network Jobs Directly and Update Network Display.




  5. If you are printing to a Hewlett-Packard (HP) LaserJet or compatible, you may have to print TrueType fonts as graphics:

    1. Run the Control Panel and choose the Printers icon.


    2. Choose the Setup button, then the Options button.


    3. Select the Print TrueType As Graphics box.




  6. If the switching box uses COM ports, try setting Windows to use hardware handshaking:

    1. Run Control Panel and choose the Ports icon.


    2. Select the port being used and choose the Settings button.


    3. In the Flow Control list box, select Hardware.


    4. Choose the OK button, then the Close button.




  7. Print to the port called LPT1.DOS (or LPT1.OS2 if it exists):

    1. Run Control Panel and choose the Printers icon.


    2. Choose the Connect button and select the LPT1.DOS port.


    3. Choose the OK button, then the Close button.


    4. Start Write and type several lines of text and change the font size and style.




  8. Print the Write document.

    If you are working with a COM port, you must add a COM1.DOS (or COM2.DOS) port to your WIN.INI file:

    1. Edit the WIN.INI file with a standard ASCII text editor (such as Notepad).


    2. Locate the [ports] section and add a new line:
      COM1.DOS=


    3. Save changes and restart Windows. You will now have a port option called COM1.DOS. Print the Write document to this port.


    COM3 and COM4 normally share IRQs with COM1 and COM2, respectively. They may not be available because of this. If your hardware supports having each COM port on a unique IRQ, then COM3 and COM4 should be usable.


  9. If the print-sharing device traps or captures a COM port, try using the MS-DOS MODE command to set up the COM port and redirect the LPT port to the COM port:

    1. Edit the AUTOEXEC.BAT file with a standard ASCII text editor (such as Notepad) and add the following lines:
      MODE COMx:9600,n,8 (where x = 1, 2, 3, or 4)

      MODE LPT1:=COMx: (this routes LPT1 to COMx)


    2. Restart your system and then restart Windows.


    3. Select the LPT1.DOS (or the LPT1.OS2) port again and try to print.


    Note: This is a workaround and may not function under all printing conditions.


  10. Print to the FILE: port and then copy the output to the printer.

    1. Run Control Panel and choose the Printers icon.


    2. Choose the Connect button, and select the port called FILE:.


    3. Choose the OK button, then the Close button.


    4. Start Write.


    5. Type several lines of text, and choose Print from the File menu.


    6. Choose the OK button.


    7. When asked for a filename, type C:\OUTPUT.PRT, and choose the OK button.


    8. Choose the MS-DOS Prompt icon and type the following command:
      copy c:\output.prt lpt1


    NOTE: Substitute the port being used for the LPT1 entry above.

    If this works, the printing problem is occurring in one of the following areas:

    • The BIOS table


    • The I/O card (LPT, COM, other)


    • The cable


    • The print-sharing device




  11. Quit Windows and run the MS-DOS Debug program to inspect the BIOS table for the correct address:

    1. Type debug and press ENTER.


    2. At the minus prompt (-), type d40:0 and press ENTER.

      The following appears:
      0040:0000 F8 03 F8 02 E8 03 E8 02-78 03 78 02 00 00 00 00
      COM1 COM2 COM3 COM4 LPT1 LPT2 LPT3


    The addresses above are the industry standard addresses for nonredirected ports. (Debug does not show the port names above).


  12. If you are using an electronic print-sharing or switching box, try slowing the polling rate it uses or the time-out setting that it uses. Refer to the manual or the manufacturer of this device for instructions on how to do this.


  13. If you still cannot print, remove the switching box and connect the printer directly to the computer. If it prints correctly, then contact the manufacturer of the print-sharing device for additional information on how to adjust the device to work in the Windows environment.


Additional query words: 3.00 3.00a 3.10 tshoot buffalo black 3.11 switchbox printsharing printshare telephone pinout true type

Keywords :
Version : WINDOWS:3.0,3.0a,3.1,3.11
Platform : WINDOWS
Issue type :


Last Reviewed: November 23, 1999
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