> For the complete documentation index, see [llms.txt](https://inacks.gitbook.io/inacks-is3720-i2c-dmx+rdm-receiver-ic/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://inacks.gitbook.io/inacks-is3720-i2c-dmx+rdm-receiver-ic/datasheet/memory-map/uid.md). # UID > This page is not the authoritative source for design information. The official [IS3720 datasheet](https://www.inacks.com/is3720) published on [www.inacks.com](http://www.inacks.com) is the authoritative reference: always consult it for the latest information. The UID registers block contain the UID number, which is a unique RDM identifier of your device. The UID is a block of 6 bytes. The first 2 bytes are the Manufacturer ID code, and the last 4 bytes is the product serial number. The Manufacturer ID codes are assigned by the ESTA, you should apply for a Manufacturer ID code at ESTA. For the application site, please refer to the following link: Manufacturer IDs 0x7FF0 through 0x7FFF are reserved for prototyping and experimental use while a manufacturer is waiting for an assigned Manufacturer ID. They are not permitted in commercial products. By default, the IS3720 uses the manufacturer code 0x7FF7, which falls within this reserved range. You should replace this code with your assigned Manufacturer ID. By default, the IS3720 comes with a random serial number intended for prototyping and experimental use. This serial number may eventually be repeated. To ensure unique identification of your products, you should program your own serial numbers. RDM messages send by the RDM controller can have 3 different destinations: 1. Unicast: The RDM message is for a specific device. 2. Full Broadcast: The RDM message is for all devices of the DMX+RDM network. This is achieved by using the special manufacturer code 0xFFFF and the special serial number 0xFFFFFFFF. 3. Manufacturer Broadcast: The RDM message is for all Responders of the same manufacturer. This is achieved by using the Manufacturer Code and the special Serial Number 0xFFFFFFFF. This register block can be read and written via I2C, and read via RDM. Under a special provisioning condition, it can also be written via RDM; refer to the Provisioning section for more information. An I2C write operation is only allowed when RDM is offline (RDM\_ONLINE = 0). This protection prevents accidental UID changes during device operation. In case of writing an invalid UID, the last valid UID will be used. This is a non-volatile register block. On each power-up, it loads its last stored value. Writing the same content to non-volatile memory that it previously held does not trigger a write cycle; therefore, it is safe to write to this register at every startup of your firmware if need. * **Name:** UID * **Description:** Unique RDM Identifier Number of your device * **Address Range:** 521 to 526 * **Memory Type:** Non-Volatile * **Accessible by:** I2C (Read/Write²), RDM (Read/Write³) * **RDM PID:** - | Addresses | Details | Default Value | Valid Range | | --------- | ------------------------------ | ------------------ | ----------------------------------------------------------------------------------- | | 521 | UID, User ID – High Byte | 0x7F |

For production: Ask ESTA for an ID.

For prototyping: 0x7FF0 to 0x7FFF.

| | 522 | UID, User ID – Low Byte | 0xF7 |

For production: Ask ESTA for an ID.

For prototyping: 0x7FF0 to 0x7FFF.

| | 523 | UID, Serial Number – High Byte | Fixed Random Value | 0x00000000 to 0xFFFFFFFE | | 524 | UID, Serial Number | Fixed Random Value | 0x00000000 to 0xFFFFFFFE | | 525 | UID, Serial Number | Fixed Random Value | 0x00000000 to 0xFFFFFFFE | | 526 | UID, Serial Number – Low Byte | Fixed Random Value | 0x00000000 to 0xFFFFFFFE | ² An I2C write operation to the UID is only allowed when RDM is offline (RDM\_ONLINE = 0). ³ An RDM write operation is only allowed during Provisioning.