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Instructions Manual
Rev 2.0 of 02/2016 41/50
7.4.1 H-CHK/L-CHK:
CheckSum of the message represented in HEX-ASCII. The Checksum is calculated executing the
exclusive OR of all the bytes sent from STX through ETX. The resulting hexadecimal value is then
converted into HEX-ASCII and the two characters representing it are sent.
WARNING: for debugging purposes, you can disable the checksum control, replacing the H-COM byte
with the value 0x44 instead of 0x35. In this case, the two bytes of the checksum are still sent but their
value is insignificant. The host computer must also manage the possibility that the checksum is
disabled.
Reply from the host computer
Upon receiving the message, the host computer must first of all send an ACK message to indicate that
the message has correctly been received and interpreted, i.e. that all the fields have the correct value
and that the checksum is correct, or a NACK message to indicate that the message contains one or
more errors: inexact checksum, incorrect length of the data field, etc.
ACK message
ACK
(0x06)
H-ADD
(0x30)
L-ADD
(0x31)
ETX
(0x0D)
ACK message timeout: 2 sec.
NACK message
where: H-ERR/L-ERR are the HEX-ASCII representation of the error code defined according to the
following table:
Error code
H-ERR
value
L-ERR
value
Meaning
0x00 0x30 0x30 Generic error
0x04 0x30 0x34 Checksum error
0x05 0x30 0x35 Field value error H-LEN/L-LEN
0x06 0x30 0x36 Data field length error
NACK message timeout: 2 sec.
7.5 REPLY MESSAGE WITH COMMAND DATA
After sending the ACK message, the host computer should send the actual reply to the message 0x50.
This reply will be identical to the message sent by VES-MATIC CUBE 30 (see paragraph 7.4.1), the
only difference being that the barcodes sent will only be those to be processed by VES-MATIC CUBE
and that the terminator will be 0x11 for “unknown codes” (i.e. not yet accepted by the host computer
and hence to be processed all the same). Therefore the
H-LEN/L-LEN and H-NUM/L-NUM fields may
be different.
If none of the barcodes need to be processed, the
Data field will contain only the H-NUM/L-NUM field
(value 0x30/0x30) and H-LEN/L-LEN will have the value 0x30/0x32.
NACK
(0x15) H-ADD
(0x30)
L-ADD
(0x31)
H-ERR L-ERR ETX
(0x0D)