Technical information

10/29/2014
Page 8 of 72
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Raw Mode
‘z’ (data) packet:
Data
(non-z) packet:example ‘i'
CodeXML® ‘i’ response example
CodeXML-start
packet-type
data
CodeXML-end
SOH
‘X’
RS
‘ap/’
‘i’
VVV…
EOT
Packet Mode
‘z’ (data) packet:
packet-start
Data
packet-end
SOH
‘X’
‘R’
‘1’
Reader ID
(4 bytes)
packet
number
(1 byte)
time
stamp
(4 bytes)
data size
(2 bytes)
data
crc16
(2 bytes)
(non-z) packet:example ‘i’
packet-start
CodeXML® ‘i’ response
packet-end
SOH
‘X’
‘R’
‘1’
Reader ID
(4 bytes)
packet
number
(1 byte)
time
stamp
(4 bytes)
data size
(2 bytes)
SOH
‘X’
RS
‘ap/’
‘i’
VVV…
EOT
crc16
(2 bytes)
Figure 1: Example 'z' and 'i' Packets in Raw and Packet Modes
Optionally, whenever the Host receives a packet, the Host will respond by sending a Y or R packet
(defined in the Host to Reader Communication section) to the Reader. If the ‘expect response’ option is
enabled in the Reader configuration, the Reader will repeatedly retransmit the packet (a configurable
number of times) until it receives a Y packet.
If a packet received by the Host has a packet-type that is not any of the valid types listed above or has
the same packet-number as the last processed packet of the corresponding type (command or data),
the entire packet – up to and including end or until timeout – should be discarded by the Host. If the
Host had requested a response, it should reissue the request.
If a packet received by the Host from the Reader fails its CRC, the Host should send an R packet to the
Reader to request that the packet be resent.