The larger of the two boards contains the connections for both antennas and is responsible for the RF side of the tracking device. Its notable chips include:

XEMICS XE1201 Ultra low power single chip transceiver

The XE1201 allows for data transmission and data reception in half duplex mode.

RFM RF1172 SAW (surface-acoustic-wave) filter

The RF1172 provides front-end selectivity (the capability to separate signals in one frequency from all other frequencies) in 433.92 MHz receivers.

Typical applications of this filter include wireless remote-control and security devices operating in Europe under ETSI I-ETS 300 220.