Page 4-18 400 SERIES INSTALLATION MANUAL
Page Rev L P/N 190-00140-02
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 400 Series unit’s GPS navigation. For the GNS 430, the MAIN OBI output may be
configured so that it sends VOR/ILS bearing information when VLOC is selected by the GNS 430 CDI
key.
The VOR OBI output provides bearing information from the active waypoint for Bendix/King Serial OBI
devices based upon the GNS 430 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
DC
.
The maximum off state leakage current with respect to ground is less than 10 µA
DC
.
4.9.3 RMI/OBI Configuration
For the GNS 430, refer to section 5.2.10 for the MAIN OBI source configuration.
4.9.4 RMI/OBI Calibration and Checkout
None.
4.9.5 RMI/OBI Interconnect
Refer to Figure 4-22 on page 4-63 for the RMI/OBI interconnect.
