Audio decoder RJ-2

FreeFlight Systems SelCal decoders deliver clear, dependable ground-to-air communication without constant radio monitoring. Designed for retrofit and mixed avionics environments, they improve crew responsiveness, reduce workload and enhance VHF and HF operations.

Why SelCal
Selective calling lets a ground station send a unique tone sequence to an individual aircraft, alerting the crew without requiring continuous radio surveillance. The result is a quieter flight deck, reduced HF noise, and immediate alerting for ATC communications.

Designed for retrofit efficiency
Compact, lightweight LRU with standard MIL-type connectors and removable pins. No jumper wires or remote switches, and seamless integration with existing VHF and HF radios.

Simplified code selection
A front-panel thumbwheel switch sets the SelCal code without wiring complexity. Sixteen tones across four codewheels give 10,920 tone combinations.

Reliable performance
Solid-state circuitry with advanced filtering delivers stable, drift-free operation, eliminating the limitations of legacy reed-based systems. High-performance decoding maintains accuracy at low signal-to-noise ratios while minimizing false alerts from unselected signals. A built-in self-test circuit verifies decoder channel integrity.

RJ2 — Rugged two-channel decoder for military and harsh environments. Qualified to DO-160F and MIL-STD 810E, 454N and 461C. Extended operating range -55°C to +85°C, 28 VDC at 320 mA, 55,000 ft. 5.14 x 2.29 x 12.84 in, 3.2 lb. Certification basis differs from the JetCall units.