As stated earlier, the 1-Wire command sequence is a three phase transaction that begins with a Master generated reset sequence. This is followed by the ROM command sequence in which the host selects a specific Slave device based on its unique ROM ID. All 1-Wire devices have a unique factory programmed 64 bit ID. The 64 bit value is subdivided into an 8 bit Family Code that is specific to the product type, 48 bits for serialization and 8 bits for a cyclical redundancy check; and a checksum for verifying data transmission integrity. Once the Master has selected a specific Slave device, the remaining devices drop off the line. The Master then executes a corresponding device level function sequence, such as a write to memory or read from memory.