109
Access Password
The Access Password is a 32-bit value stored in Reserved memory. The default (unprogrammed) value shall
be zero.
A tag with a zero-valued access password can go to
secured
state without first entering
the
open
state.
A tag with a nonzero-valued access password, then reader need to use the nonzero-valued access password
to make tag transitions the
secured
state.
A tag in the
secured
state can execute all
Access
commands (such as Read, Write, Lock, Kill tag commands),
including writing to locked blocks.
EPC Memory
EPC memory contains the following fields:
CRC-16
A 16-bit CRC calculated on the PC and EPC.
PC
(or EPC PC)
A 16-bit Protocol Control. The first 5-bits indicates length of the EPC field in Word (2-bytes size) unit.
Note
: In order to indicate the
PC
is the field stored in EPC memory, we use
EPC PC
stands for
PC
field.
EPC (or EPC ID)
The electronic product code.
Note
: In order to distinguish the
EPC
memory and
EPC
field, we use
EPC ID
stands for the
EPC
field, and
EPC
stands for the
EPC
memory.
TID Memory
TID memory contains the following fields:
Class ID
8-bits class identifier.
XTID
1 bit, XTID (
X
) indicator (whether a Tag implements an XTID)
Security indicator
1 bit (whether a Tag supports the Authenticate and/or Challenge commands)
File indicator
1 bit (whether a Tag supports the
FileOpen
command)
Tag mask-designer identifier
9 bits, (obtainable from the registration authority)
Tag model number
12 bits
