Specifications

‘S’ This character indicates that the Response Packet contains the
Zebra Printer Status requested by a ~HS (Host Status) instruction
received from the Host.
SEQUENCE # (Used to denote the current message sequence
number.) This number is identical to the message sequence number in
the Request Packet. It denotes the message sequence number to which
the Response Packet is replying.
The Response 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 sends this character as the
beginning of the variable length Data Format portion of the Response
Packet. The ASCII Control Code character STX (02H) is used as the
Start of Text Character.
DATA FORMAT (Label Information) The ‘variable length’ por-
tion of the Response Packet. If the Packet Type field in the Response
Header contains an ‘A’ or an ‘N’, no data will appear in this field. If
the Packet Type field contains an ‘S‘, this field will contain the
Printer Status Message.
ETX - (End of Text) The Zebra printer sends this character as the
end of the variable length Data Format portion of the Request Packet.
The ASCII Control Code character ETX (03H) is used as the End of
Text Character.
CRC - (Cyclic Redundancy Check) This is the CRC of the
Response Packet as calculated by the Zebra printer. This Cyclic
Redundancy Check maintains the validity and integrity of the infor-
mation transmitted between the Zebra printer and the Host computer.
This CRC is a two Byte value derived from the contents of the packet
between, but not including, the SOH character and the CRC code
itself. The Host computer will calculate a CRC of the received
Response Packet and compare it to the CRC value in this field. The
CRC of the Response Packet must match the CRC calculated by the
Host computer in order for the Response Packet to be valid.
EOT - (End of Transmission) The Zebra printer sends this character
as the end of the Response Packet. The ASCII Control Code character
EOT (04H) is used as the End of Transmission Character.
364 APPENDIX G
Error Detection Protocol