7
UPC Preamble
Three options are given for lead-in characters for UPC symbols transmitted to the host device:
No Preamble
transmitted, transmit
System Character Only
, and transmit
System Character and Country Code
(“0” for
USA). The lead-in characters are considered part of the symbol.
UPC-A Preamble
UPC-E Preamble
UPC-E1 Preamble