The GEM-PIR is an advanced PIR sensor designed for use with
Napco's GEM-Series wireless receivers. The unit is powered by
two 3-volt lithium batteries (supplied) for long service life. When
battery voltage drops below normal, a low-battery report will be
sent to the receiver (replace with Duracell DL123A or Varta/
Power-One CR123A only). Coding switches are not used in the
GEM-PIR. Each transmitter has a unique factory-programmed
RF ID code (printed on the unit) that distinguishes itself to the receiver.