When sending a single request for digital status information to the board, it will respond with the current status of the digital pin or it will respond with an error message. The command is valid for both input as output pins. 

SDIReceiveSend@SDI,<tagname>,<1|0><1|0>, true or false.
Possible error messages coming from the board
%FAT-UNKCMD-BTSERIAL, Unknown command received
%SDI-UNKCMD-BTSERIAL, Unknown tagname received