1. Do the USB to RS-422/485 Serial adapters come with termination resistors? If so, when do I need to use them and how are they configured?

2. What is the default mode of operation for the USB to RS-422/485 Serial Adapters?

3. How do I change the COM port number(s) assigned to my USB to serial adapter by Windows 2000/XP?

4. When I plug my USB Adapter into another USB port or USB hub, I get new COM port numbers. What can I do keep the same COM port assignments?

5. Can I change the properties of the ports on my USB to Serial Adapter from the software package in which I am using the ports?

6. Can I use the Advanced Options windows in Windows to configure each port on my USB to Serial Adapter separately?

7. When I unplugged my USB to serial adapter I got an error that caused my PC to reboot. How can I prevent this?

8. Why can't I get my Quatech USB adapter to perform at 460.8 kbps?

9. What can I do to increase the stability of my USB to serial adapter at high speed?

10. How do I install my USB to Serial Adapter?

11. Is there a diagnostic program I can use to determine if my USB to serial adapter is working?

12. I did not receive Windows NT 4.0 drivers with my USB to serial adapter how do I get them?

13. Where can I find out what version of the Quatech USB to Serial driver I am using?

14. When I ran the update for the new drivers for my USB to serial adapter I got a "ReadOnly File Detected" error. What should I do?

15. Do I need local administrator rights to install a Quatech USB to serial adapter?

16. What are the Operating Systems under which my USB to RS-422/485 Serial Adapter is supported?

17. How do I know if my version of Windows 98 is USB compatible?

18. What does it mean to have an unregistered Windows XP driver? Why do I get a warning screen when I install some Quatech USB drivers?

19. How do I disable the Windows XP Driver Signing check?

20. How do I uninstall my USB Adapter under Windows 98/Me/2000/XP?

21. What is the maximum number of Quatech USB to serial adapters I can use on my system?

22. Do Quatech USB to Serial Adapters contain USB hubs as well as serial ports?

23. What is the maximum data rate for USB? How about the maximum speed for Quatech USB to serial adapters?

24. I understand that USB devices are both "plug & play" and "hot-plug" capable. Does that mean that I don't need any software from Quatech to use my USB to serial adapter?

25. What does USB stand for? Where can I find out more about USB?

26. When installing a product, I get an error message stating "The System Cannot Find the File Specified." How can I fix this?

Q1. Do the USB to RS-422/485 Serial adapters come with termination resistors? If so, when do I need to use them and how are they configured?

A. Factory installed resistors allow for DSU/QSU/ESU/HSU-200/300 signal line termination in compliance with RS-422 and RS-485 standards. The desired termination can be selected or removed by configuring the associated jumper for each port. The factory default configuration is 'no termination'.

Jumpers J2 through J5 (DSU) or J2 through J9 (QSU) allow the selection of RS-422 (100 ohm) termination, RS-485 (120 ohm) termination or no termination. For normal operations over shorter distances or when using a termination in the connecting cable, the default setting will suffice. For communications over great distances or if termination via the connecting cable is not feasible, the jumpers may be configured for the desired termination.

To select RS-422 termination, move the jumpers to pins 1 & 3. For RS-485 termination, use pins 2 & 4. Ensure both jumpers are configured for each port. To access the USB adapter directly, remove the four screws on the bottom of the box and open the top cover.

Q2. What is the default mode of operation for the USB to RS-422/485 Serial Adapters?

A. The DSU/QSU/ESU/HSU-200/300 adapters operate in Full Duplex mode by default. The boards may be optionally configured by the user for Half-Duplex with RTS, Half-Duplex with DTR or Half-Duplex with Auto Transmitter Control modes of operation

Q3. How do I change the COM port number(s) assigned to my USB to serial adapter by Windows 2000/XP?

A. To change the COM port number assigned to a USB to RS-422/485 Serial Adapter follow the steps below:

1. Open the Windows Device Manager.
2. Right click on the COM port you want to change.
3. Left click on Properties.
4. Click on the Port Settings tab.
5. Click on the Advanced... button.
6. Use the drop down list to select the COM port number you want to use.
7. Click OK.
8. Click on OK again and close Device Manager.

Click here to see a screen capture of this process.

Q4. When I plug the USB adapter into another USB port or USB hub, I get new COM port numbers. What can I do to keep the same COM port assignments?

A. The easiest way to always keep the same COM port assignments is to always plug the unit into the same USB port. However, you can always reassign COM ports using the technique described above.

Q5. Can I use the Advanced Options windows in Windows to configure each port on my USB to Serial Adapter separately?

A. No. Changing any setting in the advanced options window will affect all ports on the USB adapter.

Q6. Can I change the properties of the ports on my USB to Serial Adapter from the software package in which I am using the ports?

A. No. Port properties can only be altered from the Device Manager window. Attempts to access these properties from another software program will generate an error message box that refers the user to the device manager.

Q7. When I unplugged my USB to serial adapter I got an error that caused my PC to reboot. How can I prevent this?

A. This error is caused when the USB to serial adapter is unplugged while applications are actively communicating with the device. To avoid this error, you must close any applications that are communicating on the Quatech serial port before unplugging the USB adapter.

Q8. Why can't I get my Quatech USB adapter to perform at 460.8 kbps?

A. Data rates (or baud rates) are highly system dependent. It is impossible for Quatech to know exactly how one of our products will perform in your specific system. Some major factors that affect baud rate are cabling, OS, and FIFOs. For more information about maximum data rates, see the Quatech "Serial Data Rate Information Sheet".

Q9. What can I do to increase the stability of my USB to serial adapter at high speed?

A. We recommend using your USB to RS-422/485 Serial Adapter with a 1 GHz+ Pentium compatible PC equipped with at least 128 MB of RAM.

Q10. How do I install my USB to Serial Adapter?

A. Follow these simple directions:

1. Turn on the computer and boot up the Windows 98/Me/2000/XP operating system.
2. Plug the wide flat end of the USB cable into the downstream connector located on the back of the computer or USB hub. Plug the square end of the USB cable into back of the USB box.
3. Once the cable is connected to the USB box, the "Add New Hardware Wizard" dialog window should appear.
4. Insert the Quatech COM CD into your CD ROM drive and press the "next" button.
5. Select the recommended option: 'Search for the best driver for your device' and then press the 'Next' button to proceed to the next window.
6. Select the "CD" check box and click the "Next" button to proceed to the next dialog window.
7. When the next window appears, click the 'Next' button again to view the final dialog window and then click 'Finish' to complete the installation of your USB adapter.
8. Once the adapter configuration is finished, Windows will then configure the individual serial ports (e.g. COM3, COM4) to complete the hardware installation process.
   --NOTE: It can take a long time to complete the installation of eight and sixteen port adapters because Windows installs each of the 8/16 ports individually. Be certain that you allow the entire installation process to complete or your device will not work properly.

Q11. Is there a diagnostic program I can use to determine if my USB to serial adapter is working?

A. There are several ways to go about testing the product. The easiest way for Windows users is to connect a Loopback on the Port and use HyperTerminal to test it. HyperTerminal is included with Microsoft operating systems. If you don't see it listed in Program Manager, you may need to install it from the Windows CD. RS-422/485 Loopback Instructions

Q12. I did not receive Windows NT 4.0 drivers with may USB to serial adapter, how do I get them?

A. Quatech Windows NT drivers for USB to serial adapters are now included on the the Quatech COM CD. If you have an earlier version of the CD that does not include the drivers, you can download the latest version from our website.

Q13. Where can I find out what version of the Quatech USB to Serial driver I am using?

A. Refer to the Quatech COM CD from which you installed your unit, or the installation files you downloaded to your hard-drive and used to install your USB serial port. Look for the history.txt file. Open this file and you will see the revision history for that driver. The most recent information will be at the top of the file.

Q14. When I ran the update for the new drivers for my USB to serial adapter I got a "ReadOnly File Detected" error. What should I do?

A. If you encounter this error while upgrading your USB to serial drivers, (click here to see a screen capture of this error) check off "Don't display this message again", and choose yes to continue.

Q15. Do I need local administrator rights to install a Quatech serial device?

A. Yes. When installing most kinds of hardware, you must have local admin rights or equivalent on the PC. If your computer is part of a Domain or participates in a networked environment, please contact your local LAN Administrator for assistance.

Q16. What are the Operating Systems under which my USB to RS-422/485 Serial Adapter is supported?

A. View the latest OS support matrix for USB to RS-422/485 Serial Adapter.

Q17. How do I know if my version of Windows 98 is USB compatible?

A. Download the USB evaluation utility from the USB website: www.usb.org

Q18. What does it mean to have an unregistered Windows XP driver? Why do I get a warning screen when I install some Quatech USB Drivers?

A. Microsoft has implemented a new driver signing program. This program verifies that the driver will not cause problems on the system. Although driver signing isn't a complete indication that a driver is safe or bug-free, it's certainly reasonable to assume that signed drivers are generally safer for overall system health than unsigned drivers. In addition, driver signing ensures against a Trojan horse or virus application being introduced into a driver, or having the driver replaced with other code.

However, just because a driver is unsigned DOES NOT mean that it will not function properly in your system. An "unregistered" driver is one that has not been officially tested and certified by Microsoft. Unlike previous versions of Windows, Windows XP warns users every time they try to install a driver that Microsoft has not certified. Quatech thoroughly tests all drivers before releasing them to our customers. The Microsoft XP warning has nothing to do with the quality of our driver or its ability to function properly in your system.

XP driver development is an ongoing process. All Quatech Windows XP drivers are reviewed by Microsoft for certification. However, every time we update a driver it must be re-certified. Until this certification process is complete, the updated driver will remain unsigned. Because we want to provide the best possible service for our customers, we release our XP drivers prior to receiving Microsoft certification--this gets it into your hands faster! However, we will always continue to make the most recent signed driver available even if there are more recent unsigned updates.

When you see this warning during an installation of a Quatech's Windows XP driver, simply tell Windows that you want to install the driver anyway, and continue with the standard installation process.

Q19. How do I disable the Windows XP Driver Signing check?

A. To disable Windows XP driver signing warnings, follow the steps below:

1. Double click on the System icon in Control Panel.
2. Left click on the Hardware tab.
3. Left click on the Driver Signing button. (click here for a screen cap of the Driver Signing Options Window).
4. Choose the Ignore option. Click on O.K. and then Apply and O.K.
5. Windows will not warn anymore about driver signing.

Q20. How do I uninstall my USB adapter under Windows 98/Me/2000/XP?

A. The following procedures should be used to uninstall a Quatech USB to serial adapter-- where noted specific instructions will be given for any platform dependent procedures. The uninstall procedure should be used when you want to completely delete a Quatech adapter from your system--either because you will no longer be using the adapter, or if you want to "start from scratch" with a newer version of the driver.

Step 1: Remove the product from Device Manager

1. Open Device Manager and find the "Quatech USB Devices" category and double click on it.
2. Highlight the "Quatech USB to Serial Converter" and click on the Remove button (Win9x)
   or right click on it and chose uninstall from the menu (Win2000/XP).
3. The Quatech product will now be removed from the Device Manager Tree.
4. If you do not see your Quatech Product in Device Manager please try the following (Win2k/XP Only).
   1. Enable Device Manager to view hidden devices: Start/control panel/System/Advanced/Environment Variables
   2. Under System Variables, click New.
   3. For variable name, enter "DEVMGR_SHOW_NONPRESENT_DEVICES".
   4. For value, enter 1.
   5. "OK" all the way back out.
   6. Close and reopen Device Manager. Select "View/Show Hidden Devices".
   7. As a test, there should be a new category called "Non-Plug and Play Devices." (Ignore it)
   8. Look for any Quatech related entries. Delete them.

Step 2: Delete .inf and .pnf files

1. In Windows Explorer, go to the Tools menu and select Folder Options...
2. On the View tab enable Show Hidden files and folders.
3. Uncheck Hide extensions for known file types.
4. Uncheck Hide protected operating system files (Recommended).
5. Click on Apply and O.K.
6. Find the inf folder on the left hand side of Windows Explorer. It will be located at c:\windows\inf or c:\winnt\inf (Win2k).
7. Right click on the inf folder and select Search or Find...
8. Fill in the following information for the search Results Window.
   All or part of file name: *.inf
   A word or phrase in the file: quatech
   Look in: inf
9. Click the search button.
10. The search results will list a file called msports.inf. Do nothing with this file.
11. The files of interest are anything named oem?.inf. ? meaning a number (i.e. oem3.inf). Delete the oem?.inf file that is returned for you from the c:\windows\inf folder.
12. You will also see a oem?.pnf (i.e. oem3.pnf) file. This "sister" file must also be deleted.

Q21. What is the maximum number of Quatech USB to serial adapters I can use on my system?

A. The USB specification allows for up to 127 USB peripheral devices to be used in a single system. Quatech 1-8 port adapters require one USB port, 16-port adapters require two USB ports. Thus, by using a series of hubs, up to 127 Quatech 8-port adapters or 63 16-port adapters can be used. This means that (using 127 eight port adapters) a single USB port can be used to connect 1016 serial devices.

Q22. Do Quatech USB to Serial Adapters contain USB hubs as well as serial ports?

A. No. Quatech USB to serial adapters do not also included hubs. However, you can purchase third-party USB hubs to add additional USB ports to your system.

Q23. What is the maximum data rate for USB? What is the maximum speed for Quatech USB to serial adapters?

A. The maximum data rate for USB 1.1 is 12 Mbps. USB 2.0 devices are capable of speeds up to 480 Mbps. Quatech USB 1.1 compatible serial adapters can reach speeds of 460.8 kbps--more than fast enough for most serial peripherals. Thus, there would be no advantage to implementing USB to serial adapters on the USB 2.0 standard.

Q24. I understand that USB devices are both "plug & play" and "hot-plug" capable. Does that mean that I don't need any software from Quatech to use my USB to serial adapter?

A. No. You will need to use the Quatech COM CD that comes with the product, or the installation file provided on Quatech's website, in order to configure the adapter in your system. After initial configuration, Windows will automatically recognize and configure the adapter upon insertion. The first time you plug the adapter into the USB port, Windows will bring up the "New Hardware Configuration" window to guide you through the initial configuration process.

Q25. What does USB stand for? Where can I find out more about USB?

A. USB stands for Universal Serial Bus. It is governed by "the USB Implementers Forum, Inc. a nonprofit corporation founded by the group of companies that developed the Universal Serial Bus specification. The USB-IF was formed to provide a support organization and forum for the advancement and adoption of Universal Serial Bus technology. The Forum facilitates the development of high-quality compatible USB peripherals (devices), and promotes the benefits of USB and the quality of products that have passed compliance testing". (Excerpted from the usb.org website) For more information about USB go to the USB-IF website: www.usb.org

Q26. When installing a product, I get an error message stating "The System Cannot Find the File Specified." How can I fix this?

A. Windows 2000/XP has a bug that it cannot properly detect new hardware by *.inf files, if the RunOnce registry key is missing.
This key is often used by installers to execute post-reboot programs, but sometimes they accidentally delete this key.

Go to Start » Run and enter "regedit"
Go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion
With CurrentVersion Highlighted, go to the Edit menu and select New » Key
Name the key RunOnce  - Leave everything else about the key alone.
The RunOnce key should now exist underneath the CurrentVersion key.

Reboot your PC.
Once the key exists, Windows 2000/XP stops redetecting the Hardware