RFID UHF Asset Tracking Tags Class 1 Gen 2 have a standardized and precise memory structure. RFID UHF chips by world leading manufacturers, including the ones of NXP UCODE and Impinj Monza series, follow this standard.

这是4 types of memory that the Gen2 chips are equipped with.

1. Reserved memory

2. EPC memory

3. TID memory

4. User memory

Please note that the fourth one, the user memory, is not present in all chips. Also, with the exception of reserved memory, the other three may have different sizes depending on the chip. To know the exact size, you can refer to the technical data sheet of the specific RFID asset tracking tag, or consult the technical specifications of the RFID chips.

Now let's see the 4 types of memory in detail.

1. Reserved memory

This memory bank contains the kill password and the access password (32-bit each). By default, both passwords have a value of '0', so they are disabled.

The access password can be used to lock and unlock the asset tracking tag's writing capabilities. Using the access password, the asset tracking tag can assume one of the following 4 states:

Unlocked

Perma-unlocked (can never be locked)

Locked

Perma-locked (can never be unlocked)

2. EPC memory

This memory bank is designed to contain the EPC code, or Electronic Product Code, the GS1 standard that uniquely identifies retail products. That said, the EPC memory can be used freely, for programming personal codes, service numbers, inventory numbers, serial numbers and so on.

EPC memory has a minimum of 96 bits of writable memory. EPC memory is typically used in most applications if they only need 96 bits of memory. There are some asset tracking tag which have the ability to allocate more bits to EPC memory from user memory. EPC memory is the first writable memory bank.

3. TID memory

This memory is used only to store the unique ID number of the asset tracking tag. The TID (Tag Identifier) is assigned by the manufacturer when the chip is produced. Generally, this memory is not editable.

Since the initial part of the TID identifies the company that produces the chip, each manufacturer has its own set of codes, and in general the TID code is globally unique.

4. User memory

如果你需要更多memory than the one stored in the EPC section, some chips have extended user memory which can store more information. When it comes to user memory, there is no standard on the number of memory bits that can be written to each asset tracking tag.