Samsung Galaxy TAB 10.1 GT-P7500 3MP, Wi-Fi, 3G, 16GB, Honeycomb, Dual-core Tablet (White)International Version

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Product Description

Product Description Samsung Galaxy TAB 10.1 GT-P7500 3MP, Wi-Fi, 3G, 16GB, Honeycomb, Dual-core Tablet (White)International Version

I bought this Samsung GT P7500,international version and i appreciate itsb sensitivity,sound quality
It has a very good video recording of picture and voice clarity
Bt my worry is i could not use it as a phone,when i insert a SIM card ,it still insist that:Insert Sim card.
Now my question is ,does it ned to be unlocked or something needs to be done?
I tried several diferent Sim cards,
Cant you use it with any Sim card elsewhere??
Help me i dont know what to do?