Garmin GSR 56 Installation Manual - Page 25

4.2.2 Heater Power The Heater Power inputs use series/parallel circuitry internal to the GSR 56 to enable use of either a 14V or 28V supply. The low side of Heater 2 is always grounded internally to the GSR, thus a HEATER 2 LO connection is not needed/provided. 14 V Heater Power Connections - Connect the two HEATER POWER pins (pins 21 and 36) to the 14V Aircraft Power Bus. Connect HEATER 1 HI (pin 22) to HEATER 2 HI (pin 37), and connect HEATER 1 LO (pin 38) to power ground. These connections should be made within the connector backshell. This 14V input format uses the parallel heater circuitry. 28 V Heater Power Connections - Connect the two HEATER POWER pins (pins 21 and 36) to the 28V Aircraft Power Bus, connect HEATER 2 HI (pin 37) to HEATER 1 LO (pin 38), and leave HEATER 1 HI (pin 22) floating (unconnected). These connections should be made within the connector backshell. This 28V input format uses the series heater circuitry. Pin Name HEATER POWER HEATER POWER HEATER 1 HI HEATER 1 LO HEATER 2 HI Connector Pin I/O P561 21 In P561 36 In P561 22 -- P561 38 -- P561 37 -- 4.2.3 Remote Power On The GSR 56 requires remote power-on signal to power up. IRIDIUM REMOTE_PWR_ON is a nonconfigurable discrete input conforming to: a) Low: 0 VDC < Vin < 3.5 VDC, OR Rin > 100k ohms (active) b) High: 8 VDC < Vin < 36 VDC (inactive) Pin Name IRIDIUM REMOTE POWER ON* *Denotes Active Low (Ground to activate) Connector Pin I/O P561 16 In GSR 56 Installation Manual 190-00836-00 Page 4-3 Revision F