—————————————————————————————————————————— - - ———————
|Start | Length | Cmd 1  | Cmd 2  | Data      | BCC |
—————————————————————————————————————————— - - ———————

Byte			Contents (hexadecimal value) 
0 		Start Mark (SOH, 01hex) signifies the beginning of the message
1		Length, in bytes, of the following command and data fields
2 		Command Field (1)—Explained below
3 		Command Field (2) (optional)—Explained below
4(3) 			Data Field (1) — explained below
N+3(2)		Data Field (N) — explained below
N+4(3) 		        BCC — explained below

Figure 2: PC-to-micro reader protocol.