The Bendix/King RDR 2100 Installation Manual (006-00648-0002), on page 1-1 states: "The RDR 2100 System consists of four modules: the Antenna/Receiver/ Transmitter (ART), the Radar Indicator, the System Antenna, and the Configuration Module. The system is positioned as a replacement for the RDS 86 ART."

In addition, there is a "RS-861A to ART-2100 Harness Connector Replacement" diagram in the RDR 2100 Installation Manual on page 2-107, Figure 2-50.