WEIghT_UNIT. Character string of weight unit. 1~2 byte, only possible to be:
BCC. Character of data verify. One byte. Set STA to D1, SIGN to D2, byte before
BCC to DN, so BCC=D1^D2^. .^DN.'^' is a logic XOR operator.
ETX. Symbol of ending data item, one byte, fixed at 03H.
EOT. Symbol of ending sending, one byte, fixed at 04H.
30
'TJ': catty of Taiwan, 'TL': tael of Taiwan, 'SJ': 'SJ': jin, 'LB':
pound, 'KG': kilogram, 'G': gram.