Product : Galaxy Tab > Wi-Fi Tabs > GT-P5210
The Kies program will not detect your device if the USB debugging mode is turned on. Follow the steps below to turn off USB debugging mode.
Note: If there is a green check mark next to USB debugging, then it is set on. Tap the check box to turn debugging off. Also you can turn off all the settings by sliding the Developer Options slider to the off position.
For more information about USB Debugging, please refer to The Android Developer Site at http://developer.android.com.