In Power Management, you can reduce the power consumption of any number of your computer devices or of your entire system. There is the Power Management that will turn off your monitor and your hard drive and even make your system hibernate. Of course you would want to change these settings to NEVER if you do realtime.
There is also Power Management that governs individual components used on your computer. One of the components that has this feature is your USB to Serial cable. IF this is selected and you leave the computer for a break, for instance, it will turn off the USB port making it inoperable for realtime. Below we have listed the steps you can take to disable the Power Management.
This is for Windows XP computers only.
Click on START.
Now right-click on MY COMPUTER and left-click on PROPERTIES.
Click on the hardware tab and then the Device Manager button.
In the list there will be a list of plus signs. Click on the plus next to UNIVERSAL SERIAL BUS CONTROLLERS.
When you click on the plus next to SERIAL BUS CONTROLLERS, you should see an entry that says ...ROOT HUB. There may be other text preceding the words ..ROOT HUB. If you have more than one, you will have to repeat the following steps for each one in the list.
Double-click the ROOT HUB. This will bring up a PROPERTIES window. In this window, click on the POWER MANAGEMENT tab.
In this window you will have to uncheck any check boxes. If there are some that are grayed out, That's OK.