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The VERIFY Command is not RFID Specific
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The VERIFY Command is not RFID Specific
Although the VERIFY command was added to PGL to enable the
sending of RFID data back to a host, it is not actually an RFID
command, since:
1. It does not cause any RFID activity
2. It is not restricted to RFID data.
The VERIFY command can be used to send any data expressed in
a variable (such as bar code data) back to a host.
Splitting the EPC
Customer Scenario
The customer intended to write 362501031109 to the tag as a
decimal number, but when they read the tag back they received
155693006861632597 (not what they expected).
Here Is What They Did
RFWTAG;96
64;D;*36250103*
32;D;*1109*
STOP
The problem is the way in which the decimal number was divided
up. Position matters in arithmetic. One cannot ignore the implied
leading zeros in the 32bit quantity as they are significant when the
64 bit value is non zero.
For example, 002000 is the same value as 2000, since the leading
two zeroes are insignificant. However, 2002 is not the same as 22,
since the zeroes are significant.
So when the customer chose 1109 as the LSB 32 bits, the leading
zeros were padded to the left until 32 bits were filled, resulting in
00001109. This converted to hex so that 00000455 was written into
those bits.