[Android] Check android device serial number and status in windows 7

you can use the command adb devices to check device serial number and status. 

adb devices

in my case, the command return result:

line 1)   List of devices attached
line 2)   0a204f7b            device

in line 2, the first set of number and letters is your android device serial number which connected to computer with windows platflat. the second set is the device static, it could be "device" or "offline", "offline" means the android with the specified serial number haven't connect to the computer, or no any response. "device" means the android device was connected to computer only.