Garmin GDL 90 Installation Manual

Also see for GDL 90: Installation manual

Installation Procedures2-14 560-1049-00 Rev B GDL 90 Installation Manual2.8 FUNCTIONAL DESCRIPTIONS2.8.1 POWERAircraft power is provided to the GDL 90 on the main system connector. The GDL 90 will accept inputpower from 10 to 40 VDC.P1-1 Power +P1-9 Power +P1-2 Power GroundP1-10 Power GroundRefer to Appendix C for recommended power connections.CAUTIONOperating the GDL 90 with no RF terminations on the Top or Bottom UAT Antennaports can result in equipment damage. Always operate the GDL 90 with the Top andBottom UAT Antenna ports terminated with a VSWR ratio of 3.0:1 or less.2.8.2 MICRO AIRCRAFT PERSONALITY MODULE (μAPM)The GDL 90 stores installation-specific configuration information in an aircraft personality modulelocated on the rear of the mounting tray. This eliminates the need to set up the configuration again if anew GDL 90 is installed. Since APM contains no lightning protection, the wire length from APM toGDL 90 must be limited to 4 inches maximum.P1-6 APM TxDP1-7 APM RxDP1-14 APM GndRefer to Appendix C for interconnect information.2.8.3 STATUS LEDSThe GDL 90 uses 6 LEDs mounted on the front of its enclosure to communicate system status andconditions of various internal functions. The descriptions of the LEDs, with power applied to the unit,are as follows:Name DescriptionTx UAT Transmit – normally LED blinks at once a secondON = UAT data is being transmittedOFF = No UAT transmissionRx UAT ReceiveON = UAT data is being receivedOFF = No UAT receptionMaint MaintenanceON = GDL 90 needs maintenance check at the earliest convenienceOFF = No maintenance issue