Specifications

DST. Z-ID (Destination Zebra-ID) This is the three digit ASCII
I.D. number used to identify which Zebra printer is to receive the
Request Packet. The Zebra printer compares this number to the Net-
work ID number assigned to it during Printer Configuration. The
Zebra printer will act on the Request Packet only if these numbers
match.
SRC. Z-ID (Source Zebra-ID) This is a three digit ASCII number
used to identify the Host computer. This number is determined by the
user.
TYPE (Packet Type) This field is used to define the type of Request
Packet being sent by the Host. Only two characters are valid in this
field.
‘P’ indicates a Print Request Packet
‘I’ indicates an Initialize Request Packet
Most of the Packets sent by the Host to the Zebra printer will be of the
‘P’ variety, requesting a label to be printed.
The ‘I’ character tells the Zebra printer to initialize the packet
sequence numbering. It is required in the first packet of a new
printing session, after starting up the Host computer or the Zebra
printer.
SEQUENCE # (The Sequence Number of the Request Packet)
This block contains a single digit number used to denote the current
Transaction Number. The Host computer must increment this number
by “1" for each new Request/Response Transaction pair, i.e. 0, 1, 2,...,
9. The numbers repeat after every 10 Transactions.
The Request Packet Data Block is comprised of four fixed-length fields
and one variable-length field. These fields are defined as follows.
STX - (Start of Text) The Zebra printer interprets this character as
the beginning of the variable-length Data Format portion of the
Request Packet. The ASCII Control Code character STX (02H) is
used as the Start of Text Character.
DATA FORMAT (Label Information) A variable-length portion
of the Request Packet that contains the complete or partial ZPL II
label format, or partial data string (such as a downloaded graphic).
APPENDIX G 361
Error Detection Protocol