I have lately seen quite few people complain that their Samsung Galaxy S3 (Same symptoms seems to exist in the Galaxy S4 & Galaxy S2) could charge when connected to their laptop, but could not detect it as a USB connection. You might need your Android phone to detect your laptop USB connection to be able to tether internet or just to move files across. If you are facing such a problem, I would suggest you try the below different solutions:
Option#1: If “Connected as usb device” show up in your pull down notification shade, then click on it and switch to PTP mode and that should fix it.
- Shutdown your phone
- Remove your battery
- Remove your SD Card
- Wait couple of minutes
- Put your SD Card and battery back
- Power on your phone, though make sure it is not connected to USB yet
- After your phone has completed it is power on cycle connect it to your USB cable and test.
Option#3: If the above two options does not work, make sure you are using a supported USB cable preferably the original one that came with your phone. Maybe borrow a known working cable from a friend to test it.
Option#4: If none of the above work, it might be your phone or laptop have a problem and it is time to visit a repair center.
Hope this help and enjoy your Android Power.