Defining The Size Of The EPC Data That Can Be Encoded For GEN2 RFID Tags

Article ID: 13695564



Issue / Question

Trying to encode more than 96bits of data fails when EPC memory bank has more than 96bits available.

How to increase or decrease the protocol control bits of the EPC memory bank.

Applicable To

ZD500R, R110Xi4, R110PAX4, RZ600, RZ400, ZE500R, R110XiIII Plus UHF, R110XiIII Plus HF, ZT620R, ZT420R, ZT610R, ZT410R, RP4T, ZPL

Resolution / Answer


Changing the Protocol Control (PC) bits in order to encode more or less than the default 96bits on GEN2 RFID Tags.


With Gen2 tags, there's an area of memory (in the EPC bank) that defines how a reader will backscatter the data. Think of it as a filter and the reader will only return the defined number of bits. The protocol control bits is the area of memory that defines the amount of the EPC data. Up till now it's generally been fixed at 96bits. You are now able to increase or decrease this value.


Customers wanting to use a value of 240 bits for example can change the protocol control bits to the desired size.

This command will set the protocol control to 240 bits:



This is based on this table Read More>>

As you can see, 7800 gives you 240 EPC bits.  This is actually defined in the Gen2 spec.  Encoding the tag requires slightly different ZPL than for a 96-bit tag.

This command:



Will encode the 240bits (30 bytes) of data.

Notice that both of these commands are writing to the EPC memory bank (see the "m" parameter of the ^RF command).  The "1" EPC area is different than the "E" memory bank (which is 96-bits). 

Here are details related to the difference between the "E" memory and  "1" memory of the ^RF command. Read More>>

To summarize:



This will encode the 240 bits.


If the above does not work, check that the tag you are using does have the amount of EPC memory that you are trying to encode to.
For details of how to check the EPC memory size of the tag you are using, Click Here>>


Helpful Information

RFID Commands from the ZPL Manual Read More>>

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