TIP-6.1 Standard
Smart contracts in TVM can implement a wide variety of functionality - wallets, tokens, exchanges and so on. We need a standard way to determine the type of smart contract without relying on knowledge of its internal structure.
Regarding to that a standard has been developed known as TIP.6, which offers the desired functionality.
The SID interface is part of the TIP-6.1 standard, as defined in the TVM Network documentation. It defines a smart contract interface that allows other contracts to query if a contract implements a specific interface.
TIP
Also refer to the provided links below fot further information.