Garmin GNC 420AW, Installation Manual

Page: 82 / 236

Page 4-20 400W Series Installation Manual
Rev. G 190-00356-02
4.9 RMI/OBI
4.9.1 RMI/OBI Function
The MAIN OBI output provides bearing information from the active waypoint for Bendix/King Serial
OBI devices based upon the 400W Series unit’s GPS navigation. For the GNS 430W, the MAIN OBI
output may be configured so that it sends VOR/ILS bearing information when VLOC is selected by the
GNS 430W CDI key.
The VOR OBI output provides bearing information from the currently tuned VOR station for
Bendix/King Serial OBI devices based upon the GNS 430W VOR receiver. When a localizer channel is
tuned on the VLOC window, there is a bit in the data stream set to indicate that a localizer frequency is
tuned which stows the needle or drives it to the 3 o’clock position.
4.9.2 RMI/OBI Electrical Characteristics
Pin Name Connector Pin I/O
MAIN OBI CLOCK P4001 43 Out
MAIN OBI SYNC P4001 45 Out
MAIN OBI DATA P4001 44 Out
Pin Name Connector Pin I/O
VOR OBI CLOCK P4006 25 Out
VOR OBI SYNC P4006 26 Out
VOR OBI DATA P4006 27 Out
The output driver is active low. The driver output voltage is not more than 1.0 V when sinking 20 mA.
The maximum off state leakage current with respect to ground is less than 10
μ
A.
4.9.3 RMI/OBI Configuration
For the GNS 430W, refer to Section 5.3.11 for the MAIN OBI source configuration.
4.9.4 RMI/OBI Calibration and Checkout
Refer to Section 5.5.6.11 for calibration and checkout.
4.9.5 RMI/OBI Interconnect
Refer to Figure H-21 for the RMI/OBI interconnect.