15
Communication Protocol
GS1100 communications protocol has been extended to accommodate several new
commands. At the same time, backward compatibility is maintained with earlier device
version (GS1000A).
Communications between the GS1100 and PC take place in the form of commands sent
by PC side and replies from GS1100. Commands and replies are packets of data using
ASCII control characters to mark beginning and ending of packets.
Control characters used by the GS1100 communications protocol are summarized
below:
Baud rate: 19200 bps, None parity,8 data bits,1 stop,
CONTROL CHARACTER TABLE
ITEM
Hex
Control Key
Function
STX
02H
^B
Marks the beginning of data packet
ETX
03H
^C
Marks the ending of data packet
EOT
04H
^D
Indicates the end of data exchange
ENQ
05H
^E
Marks the beginning of command packet
ACK
06H
^F
Acknowledges reception of data
NAK
15H
^U
Requests data retransmission
ETB
17H
^W
Signals that command or data was not accepted
There are two different packet types: command packets and data packets.
Command packets start with ENQ character and contain a machine number of the
GS1100 addressed and command code.
COMMAND FORMAT
ENQ
machine number
command code
1 character
2 characters
1 character
Machine number is supplied as a two-character Hex string and can be in the 00H...FFH
range (for example, machine number of 4AH is represented by „4A‟ ASCII string). 00H is a
so-called universal machine number, it will work with any GS1100, regardless of its
machine number setting. When using machine number other than 00, make sure that it
matches current machine number of the GS1100 (set by “P” command). Using universal
machine number of 00 will work well in all situations.
