The DS1990A Serial Number iButton is a rugged data carrier that acts as an electronic registration number for automatic identification. The DS1990A consists of a factory-lasered, 64-bit ROM that includes an unique 48-bit serial number, an 8-bit CRC and an 8-bit Family Code (01h). Data is transferred serially via the 1-Wire protocol which requires only a single data lead and a ground return. The DS1990A is fully compatible with the DS1990 Serial Number iButton but provides the additional 1-Wire protocol capability that allows the Search ROM command to be interpreted by the DS1990A and therefore allows multiple DS1990A devices to reside on a single data line.
? Upgrade of DS1990 allows multiple Serial Number iButtons to reside on a common bus
? Unique 48?bit serial number
? Low-cost electronic key for access control
? 8-bit CRC for checking data integrity
? Can be read in less than 5 ms
? Operating temperature range of -40°C to +85°C
Common iButton Features
? Digital Identification and Information by Momentary Contact.
? Unique, Factory-Lasered and Tested 64-Bit Registration Number (8-Bit Family Code + 48-Bit Serial Number + 8-Bit CRC Tester) - Assures Absolute Traceability Because no Two Parts are alike.
? Multidrop Controller for 1-Wire Net.
? Chip-Based Data Carrier Compactly Stores Information.
? Data Can be Accessed While Affixed to Object.
? Button Shape is Self-Aligning with Cup-Shaped Probes.
? Durable Stainless Steel Case Engraved with Registration Number Withstands Harsh Environments.
? Easily Affixed with Self-Stick Adhesive Backing, Latched by its Flange, or Locked with a Ring Pressed Onto its Rim.
? Presence Detector Acknowledges When Reader First Applies Voltage.
? Meets UL#913 (4th Edit.). Intrinsically Safe Apparatus: Approved Under Entity Concept for Use in Class I, Division 1, Group A, B, C and D Locations (application pending).