RFID Communications
LRP2000 Passive Reader/Writer 90
6.5 ABx Fast Protocol
The ABx Fast protocol differs from the Abx Standard Protocol in that the atomic data element is a byte
instead of a 16-bit word. ABx Fast commands and responses also contain a two-byte word to indicate the
size of the packet being sent. ABx Fast also supports the use of a one-byte checksum.
Packet Size
The ABx Fast protocol requires that the size of the packet be included following the terminator in every
packet. All parameters and data between the packet size byte and the checksum (if used), or terminator
bytes (if not using the checksum) must be accounted for in the packet size word. The packet size will be
the same with or without a checksum.
Checksum
The optional checksum must be enabled from the operating mode menu to be available. The checksum is
calculated by adding all the byte values in the packet (less the values in the header, checksum if present,
and terminator), discarding byte overflow, and subtracting the byte sum from FFH. Thus, when the packet
length through the checksum are added as byte values, the sum will be FFH.
Example
The following is a typical command using a checksum.
Field Contents
Header 0202H
Command Size 0003H
Command Code 01H
Timeout 07D0H
Checksum 24H
Terminator 03H