iPhone 4S iOS 5.1 - NO Audio (Audio bug). SOLUTION under Video

iPhone4S iOS 5.1 - NO Audio. SOLUTION → it was a problem due to the use of the Chinese Docking Station, as well as micro particles of dust, on the iPhone's 30-pin connector. After cleaning brush with alcohol the problem went away. :)) ------ In the video you will not see how to clean the connector. I tried different ways to get the sound on the speaker and the sound slider on the screen. After the test call to any phone numbers and enabling/disabling of speaker audio sometimes it works.