Appendix S – RFID Overview 
 
Class Series 2 Programmer’s Manual   301 
 
Field  Valid Inputs  Meaning 
a 
1, 2, and 3 
Operation to perform, where:  
1 = Read (report to host)  
2 = Write 
3 = Write / Verify
 
bbb 
Wnx   RFID Hexadecimal Operation, where no “n” is an implied 1. 
c 
0  Not Used, should be 0 
d 
0  Not Used, should be 0 
HF:  Lock after write, where:  
 
 
x = 0 – Use printer setup to determine if lock is performed. 
 
 
x = 1 – Lock after write. 
 
    yy = Not Used 
UHF EPC Gen2:  Lock after write, where:  
 
 
x = 0 – Use printer setup to determine if lock is performed. 
 
 
x = 1 – Lock after write. 
 
    yy = Lock state where “01”is for permalock, “10” for pwd-
write lock or “11” for both states  
eee 
xyy 
UHF other tag types: Not Used, should be 000 
HF: Starting block number to write. 
UHF EPC Gen2: Block address where “0001” is EPC data, “0002” 
is Tag ID or “0003” is user memory. Using “0000” is for EPC 
data also (for backwards compatibility). 
ffff 
0000 – 9998 
UHF other tag types: Not Used, should be 0000 
HF: Not Used, should be 0000 
UHF EPC Gen2: Data word offset – currently only used for read 
operation 
gggg 
0000 
UHF other tag types: Not Used, should be 0000 
hhhh 
Four-digit decimal 
data byte count.  
Number of bytes to follow (to include all bytes that follow until 
the end of the data). 
 
 UHF data length must be 8 or 12 for EPC, 8 for Tag ID or 
multiples of 2 for user memory sections. 
jj…j 
Valid ASCII character 
string followed by a 
termination 
character. 
Data to write to the tag.  
 
 UHF data length must be 8 or 12 for EPC, 8 for Tag ID or 
multiples of 2 for user memory sections.