A stored procedure communicates with the calling program through its parameters. When a program executes a stored procedure, it can pass values to the stored procedure through the parameters of the stored procedure. These values can be used as standard variables in the Transact-SQL programming language. The stored procedure can also return values to the calling program through OUTPUT parameters. A stored procedure can have as many as 2100 parameters, with each parameter having a name, data type, direction, and default value.