The String command converts the input number to a base-2 string, by default in least-to-most significant bit order. Specification of the option msbfirst reverses the order in the output string to most-to-least significant bit order.

The most common usage of this command would be for conversion of a number into a string of its base-2 digits.

The option bits=n tells String how many bits to consider in the conversion. Any bits in a higher position are simply ignored.