Garmin GTX 327 Installation Manual

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Page 14 GTX 327 Installation ManualRev J 190-00187-022.6.1 Power and Lighting FunctionPower Input requirements and Lighting Bus input are listed in the following tables. The power-input pinaccepts 11-33 Vdc. Switched Power Out is a power source available for devices such as a remote digitalaltitude encoder. Refer to figure B4 on page 43 for power and lighting interconnections.2.6.1.1 Aircraft PowerTable 2-5. Aircraft Power Pin AssignmentsPIN NAME PIN NUMBER I/OAIRCRAFT POWER 15 InSWITCHED POWER OUT 14 OutPOWER GROUND 13 --POWER GROUND 25 --2.6.1.2 Lighting BusThe GTX 327 unit can be configured to track a 28 Vdc, 14 Vdc, 5 Vdc or 5 Vac lighting bus using theseinputs. The GTX 327 can also automatically adjust for ambient lighting conditions based on thephotocell. Refer to sections 3.3.2 and 3.3.3 for lighting configuration.Table 2-6. Aircraft Lighting Pin AssignmentsPIN NAME PIN NUMBER I/O14 V/5 V LIGHTING BUS HI 24 In28 V LIGHTING BUS HI 23 In2.6.2 Altitude FunctionsParallel gray code altitude inputs are considered active if either the voltage to ground is < 1.9 V or theresistance to ground is < 375 Ω. These inputs are considered inactive if the voltage to ground is11-33 Vdc. Refer to figure B4 on page 43 for parallel gray code and serial data altitude interconnections.Carefully check encoder input lines for correct connection after wiring is complete.NOTESThe GTX 327 contains internal altitude code line isolation diodes toprevent the unit from pulling the encoder lines to ground when thetransponder is turned off.For altimeters that can be connected in both serial data and parallel graycode format, such as the Garmin GAE 43 (Garmin P/N 013-00066-00),select one or the other but not both wiring connections.