Why when I insert a sim card the tablet said invalid card
I insert more than one sim card and they are all working on other devise but in my tablet said invalid card
The third generation of the Samsung Galaxy tablet with a 7-in. screen announced on June 24, 2013. Repair of this device requires screwdrivers and prying tools. The device is available in white or gold brown with 8, 16, or 32 GB of storage, and includes a microSD slot that can hold up to an additional 64 GB of memory.
Is your tablet locked to a certain carrier? You can unlock your device if its not still under contract then it would be possible to use any sim. the original carrier will unlock for a fee or you can use an unlock service off the internet. Or if your ambitious you can root your device and learn from hack sites how to unlock it yourself . Hope this helps
most likely because your tablet is locked to a specific carrier. the only way to get another sim card to work in htis instance is to unlock it. luckily you can call the carrier and as long as you don't owe money then they will give you the unlock code for it