There is no restriction on the length of EPC ID that can be written via RFIDSample3Plus application on MC3090-Z. User can follow steps below to write 128 bit EPC ID 1. In order to see tag's EPC ID whose length is greater than 96 bits, user should go to "Tag Storage Setting" window to set the maximum Tag ID length to a proper value, In this case, it shuld be 16 (bytes)  ( Menu -> Operations -> Tag Storage Settings ) 2. If there is only one tag in the RF field that needs to be written, set the tag population value to 1 for both antennas (antenna index 1 & 2). This value can be set in Singulation window ( Menu -> Config -> Configuration -> Singulation) 3. Set both antennas' power value to the max value(30 dBm) in the Antenna Config window ( Menu -> Config -> Configuration -> Antenna ) 4. Write EPC ID in the Write Tag window  Brief explanation on the various parameters in “Write Tag” Form  Tag ID:  EPC ID of the selected tag Password: If the tag has been locked, you need to enter the correct password before performing                 the write operation. If tag is not locked, then just enter 0 Memory Bank: select tag memory bank for write operation.                  -   EPC MB: store tag’s EPC ID                   -   Reserved MB: contain tag’s kill and access passwords                   -   TID MB: Typically store tag’s chip info                    -   User MB: store user-specific data    Offset: Offset of the first word to be written     Length: the length of data     Write Data - The data to write to the selected tag  Note: The unit of both offset and Length is byte. And length should also be on word (2 bytes)            boundaries. In other words, it should be an even number If you try to write 128 bit EPC ID, the Write Parameter settings should be:                  Tag ID:  the selected tag's EPC ID in hex formate                   Password:  0                Memory Bank: EPC                  Offset(Bytes):   4   ( bypass the CRC and PC words )                Length(Bytes):  16                Data(Hex):  total of 32 hex characters    Hope the above information will be helpful! Thanks! Rui