char * Send_Command( Select_Reader * Reader, COMMAND Command, char * Data)
{
   char * Reader_Reply;

   // reader does not exist or command execution is impossible
   if( ! Reader || ! Reader -> Commands [Command].Procedure)
          return( "N??00");

   if( Command == INITIALIZE)
           Reader -> State = USABLE;

   return( (* Reader -> Commands[Command].Procedure)

                         ( Reader, Reader -> Commands[Command].Parameter ?
                                           Reader -> Commands[Command].Parameter : Data));
};