41 Transmit All ID Codes
!41
instructs the reader to transmit all IDs without regard for uniqueness. This command
can be useful when mapping the footprint or performing diagnostics.
After diagnostics are complete, you may want to reinstate the uniqueness check using
command
!410N
Select Unique ID Code Criteria, or by using
!40
to set reader back to
its original setting.
Reader response:
!Done
410N Select Unique ID Code Criteria (Anti-passback Feature)
!410N
instructs the reader to buffer and transmit ID codes according to the following test:
an ID is read if previously decoded IDs have changed value at least
N+1
times since
the new ID was last received. IDs that do not pass the test are not read.
The factory-
default setting is command
!4100,
which selects a separation of one ID.
Variable
N
specifies ID separation as shown in
Table 10 Unique ID Code Criteria
Command
Uniqueness Criteria
4100
Separation of 1 ID (factory default)
4101
Separation of 2 IDs
4102
Separation of 3 IDs
4103
Separation of 4 IDs
Each time the reader receives a tag ID, it compares the ID with the contents of a
comparison register. This register contains the following four items:
Item 1
Most recently acquired ID
Item 2
Second-most recently acquired ID
Item 3
Third-most recently acquired ID
Item 4
Fourth-most recently acquired ID
When the uniqueness filter is set to separation of one ID, the newly acquired ID
is transmitted only if it is different from the first item. Separation of two IDs allows
transmission if the new ID is different from Items 1 and 2 in the comparison register.
Separation of three and four IDs transmit the new ID only if it is different from the first
three and the first four items, respectively.
Note: A new ID can fail the filter test and not be transmitted; however, it
remains stored in the comparison register.
The uniqueness test’s time limit is set by Command
!441
. If an ID is buffered, it will
not be accepted again unless it arrives at the reader more than the programmed time
interval from the previous arrival or until the receipt of one or more other IDs reset the
uniqueness.
Reader response:
!Done
Chapter 6 Commands
TransCore Proprietary
6–31