Com Discrete Inputs - Garmin GTR 225 Installation Manual

5.2.5

COM Discrete Inputs

Active-Low discrete inputs are considered active if either the voltage to ground is ≤3.5 VDC or the
resistance to ground is ≤375 . These inputs are considered inactive if the voltage to ground is
6.5-33 VDC or the resistance to ground is >100 k.
Active-High discrete inputs are considered active if the voltage to ground is >6.5 VDC. These inputs are
considered inactive if the voltage to ground is ≤3.5 VDC or the resistance to ground is ≤375 .
COM MIC 1 KEY*
INTERCOM ENABLE*
COM MIC 2 KEY*
COM REMOTE TRANSFER*
COM REMOTE TUNE UP*
COM REMOTE TUNE DOWN*
TEST MODE*
An asterisk (*) following a signal name denotes that the signal is an Active-Low, requiring a ground to
activate. If there is no asterisk, the signal is an Active-High.
5.2.5.1 COM MIC 1 KEY*
COM MIC 1 KEY* discrete input, when pulled low, allows the audio that is present on the COM MIC 1
AUDIO IN HI (P2001-5) to be transmitted over the radio.
5.2.5.2 INTERCOM ENABLE*
The INTERCOM ENABLE* discrete input enables the intercom function of the GTR/GNC when
grounded. This input can be connected to a switch, that, when activated, will enable the intercom function.
There is also a menu option to enable the intercom if it is not desired to utilize a remote switch.
5.2.5.3 COM MIC 2 KEY*
COM MIC 2 KEY* discrete input, when pulled low, allows the audio that is present on the COM MIC 2
AUDIO IN HI (P2001-6) to be transmitted over the radio.
5.2.5.4 COM REMOTE TRANSFER*
COM REMOTE TRANSFER* discrete input may be used to flip-flop between the active and standby
COM frequencies. A momentary low on this pin will load the standby COM frequency into the active
COM frequency field and place the active frequency into the standby COM frequency field.
COM REMOTE TRANSFER* input may be used for emergency operation of the COM transmitter. If the
switch is depressed for two seconds, the active COM frequency changes to 121.500 MHz. Once the
emergency frequency is activated through COM REMOTE TRANSFER*, the GTR/GNC transceiver
ignores inputs from the front panel controls for COM selections only. The pilot may exit this independent
mode—restoring COM selection control to the front panel knobs and keys—by again depressing the
switch for two seconds.
190-01182-02
Rev. B
Pin Name
Connector
P2001
P2001
P2001
P2001
P2001
P2001
P2001
GTR 225/GNC 255 TSO Installation Manual
Pin I/O
11 In
12 In
26 In
27 In
28 In
29 In
41 In
Page 5-9