Samsung used a USB cable for some of its earlier tablets that, on the tablet end, looked identical to an Apple 30-pin plug. However, it was not the same and not interchangeable. Also called a "Galaxy Tab" connector, dual-charging cables are available that have USB on one end and both Apple 30-pin and Samsung 30-pin plugs at the other. See Samsung Micro USB
They Look Like Twins
On very close inspection, there are differences, and the Samsung plug did not fit into Apple's earlier 30-pin socket, and vice versa.