SohoBasic USB Serial Converter DOS Box Support Version 2.0 This version of the serial converter drivers provides support for programs running in a DOS session under Windows 95 or Windows 98. DOS box support is enabled from within the Device Manager. Right-click the 'My Computer' icon on the desktop and select 'Properties'. Click on the Device Manager tab. From within the Device Manager, click the '+' sign beside the 'Ports' section. This will expand that section to show all of the communication ports on your machine. Select the 'USB Serial Port' and click 'Properties'. Click on the 'DOS Box' tab. Click on 'Enable DOS Box 16550 emulation' to select DOS support. After selecting the DOS Box emulation, you will have to choose the COM port that DOS uses to communicate with the serial converter. This can be the same COM port that the converter is already using. Select the COM port name from the drop-down list. DOS programs communicate with serial ports using an interrupt (IRQ) and an I/O address. There are a limited number of IRQs available for use - the typical machine only has 14. Most of these are already used by other systems inside your computer. For instance, your hard drive system and your mouse will usually each use an interrupt. The following table shows the standard IRQ and I/O assignments for COM1 - COM4. These values should work with most DOS programs. Port IRQ I/O -------------------- 1 4 03F8 2 3 02F8 3 4 03E8 4 3 02E8 COM1 and COM3 share IRQ4. This means that COM1 and COM3 cannot be used simultaneously, since a program cannot tell which port is actually receiving data. Since COM2 and COM4 also share an interrupt they have the same restriction. Unless DOS box support is enabled, the serial converter does not normally use an interrupt, so this does not affect it. However, if DOS support is turned on, a USB DOS Serial Port Emulator will be installed. This emulator uses both an IRQ and an I/O address and is affected by the normal COM port restrictions. To avoid having a conflict, it is possible to assign a COM port a different interrupt or I/O address. In order to do this you should select the COMX option. The DOS box emulator will choose an IRQ and I/O address that do not conflict with your other hardware. You can view the settings it chose from the 'DOS Box' tab in the properties page. If you wish to modify these settings, select the 'USB DOS Serial Port Emulator' device and click 'Properties'. Go to the 'Resources' tab and uncheck the 'Use automatic settings' checkbox. Then select either the 'Input/Output Range' or the 'Interrupt Request' and click 'Change Setting' to enter your own value. However, since you are overriding the automatic selection your choice may conflict with other hardware installed in your computer. If you select the COMX option you will need to configure your DOS program to use non-standard IRQ and I/O addresses. Check the manual or instructions that came with your program for information on setting these parameters. Since many programs cannot access non-standard COM ports, try to use COM1 - COM4 if possible. On some computers, after you have enabled DOS box support, Windows will detect an IRQ conflict between the built-in COM ports and the USB Serial Port. In this case it may reassign the resources that the built-in COM port is using. It will also occasionally renumber the built-in COM port so that it is past COM4. Either of these actions may cause your existing programs to stop working with the built-in COM port. In this case try resetting the original COM port and using a different COM port name for the serial converter DOS box emulation. To reset the original COM port temporarily disable DOS box support by unchecking the 'Enable DOS Box 16550 emulation' checkbox. Then select the built-in COM port and click 'Remove'. After restarting your computer Windows should redetect the original COM port and assign it the correct name and resources. Due to the limited number of interrupts, it may not be possible to find a free IRQ in your computer. In this case DOS box emulation may not work without a conflict.Download Driver Pack
After your driver has been downloaded, follow these simple steps to install it.
Expand the archive file (if the download file is in zip or rar format).
If the expanded file has an .exe extension, double click it and follow the installation instructions.
Otherwise, open Device Manager by right-clicking the Start menu and selecting Device Manager.
Find the device and model you want to update in the device list.
Double-click on it to open the Properties dialog box.
From the Properties dialog box, select the Driver tab.
Click the Update Driver button, then follow the instructions.
Very important: You must reboot your system to ensure that any driver updates have taken effect.
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