Newland NLS-FM30 Series User Manual page 30

Example:
Write 0x3E into register 0x000A
1) Write operation succeeds:
Command sent: 0x7E 0x00 0x08 0x01
Message received: 0x02 0x00 0x00 0x01 0x00
2) CRC check fails:
Command sent: 0x7E 0x00 0x08 0x01
Message received: 0x02 0x00 0x01 0x01 0x00
3) Situations that may cause the scanner to respond with an invalid command message: Command sent
is shorter than the required length, or the third byte is not sent out within 400ms after the first two bytes
"0x7e 0x00" are sent
Command sent: 0x7E 0x00 0x08 0x01
Message received: 0x02 0x00 0x03 0x01 0x00
0x00 0x0A 0x3E 0x4C 0xCF
0x33 0x31
0x00 0x0A 0x3E 0x11 0x22
0x04 0x01
0x00 0x0A 0x3E
0x6A 0x61
22