User Manual Part 1

LRP2000 Long Range Passice Reader/Writer
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6
RFID Interface
6.1 Introduction
Conventions
In this manual, numbers expressed in Hexadecimal are appended
with "H." For example, the number of fingers on a typical person will
be expressed either as "10" in decimal or as "AH" in hexadecimal.
The addresses of the bytes of read/write memory within an RFID tag
are numbered from 0 to N, where N is one less than the number of
read/write bytes in the tag. The number of read/write bytes is equal to
the Block Size multiplied by the Number of Blocks. These parameters
can be found for a particular tag using the ABx Command 16H, Get
Label Information.
Command protocols
The LRP2000 offers three possible command protocols: ABx
Standard, ABx Fast and ABx ASCII. The ABx Standard format is
word-based and shares a common syntax with most existing RFID
systems produced by Escort Memory Systems.The ABx Fast and ABx
ASCII protocols are byte-based packet structures that permit
command execution with fewer total bytes transferred. Escort
Memory Systems offers more support for ABx Fast protocol in terms
of examples and demonstration software. Because of this, and the
fact that ABx Fast speeds communication while increasing error
immunity, operators are encouraged to implement ABx Fast protocol.
The commands in all three protocols consist of the same basic
structure. They comprise a header, a number of parameters, and a
command terminator. The headers and terminators are unique to each
protocol, but are the same for every command within one protocol. For
example, in ABx Standard, every command begins with the one-byte
header "AAH," and ends with the two-byte terminator "FFFFH". In ABx
Fast and in ABx ASCII, every command begins with the 0202H, and
ends with 03H. Like the commands, the responses from the controller
comprise a header, a number of response codes and data, and a
response terminator. The headers and terminators are the same for
the responses as they are for the commands. The ABx command set
is made of three subsets: the single-tag commands, multi-tag
commands, and user I/O commands. The single-tag commands
perform read/write operations on exactly one tag in the range of the
antenna at a time. The presence of more than one tag within the
range of the antenna may cause RFID communication errors. To
avoid these errors, the multi-tag commands allow for simultaneous