FT232R USB UART and Android Device

FT232R USB UART and Android Device

I am now working on communicating with android device with the FT232R USB
UART .If I insert the Ft232R cable into the SAMSUNG Nexus,it works
well(the test app is provided by offical
website:http://www.ftdichip.com/Android.htm),but when I insert it into my
aigopad,the aigopad can not read any info from the FT232R,the device show
that:the device number: 0.So I am sure there is something wrong with my
aigopad,but I do not where is the problem.
My device is aigopad M608 and the android version is 4.0.4.
Looking forward to your help!