The DS1990R Serial Number iButton
is a rugged
data carrier that serves as an electronic registration
number for automatic identification. Data is transferred
serially through the 1-Wire
protocol, which
requires only a single data lead and a ground return.
Every DS1990R is factory lasered with a guaranteed
unique 64-bit registration number that allows for
absolute traceability. The durable stainless-steel
iButton package is highly resistant to environmental
hazards such as dirt, moisture, and shock. Its
compact coin-shaped profile is self-aligning with
mating receptacles, allowing the DS1990R to be
used easily by human operators. Accessories permit
the DS1990R iButton to be mounted on almost any
object, including containers, pallets, and bags. The
DS1990R is a fully compatible variant of the
DS1990A. In applications where a presence pulse on
contact is critical the DS1990R should be preferred
over the DS1990A.