Garmin GDL 69/69A Installation Manual page 41

3.2.5 Discrete Inputs (GDL 69A Only)
The discrete inputs are used to control the XM radio channels and volume. All of these inputs are active
low (i.e. grounded when active, and open otherwise). Each input presents a load of greater than 10 kΩ.
3.2.5.1 Audio Volume Inputs (Up, Down, Mute)
The Up, Down, and Mute discrete provides audio volume control of the audio output. (Note: The volume
and mute controls have no affect on the Line Out output volume.)
P691-73 Volume increment
P691-74 Volume decrement
P691-70 Audio Mute
3.2.5.2 Audio Channel Control Inputs (Up, Down)
P691-71 Channel Increment
P691-72 Channel Decrement
3.2.5.3 Audio Suppression Inputs
There are six discrete inputs for audio suppression. There are three active low and three active high
inputs. The Audio Suppression inputs suppress the Audio Out output by activating any one of multiple
inputs. The threshold voltages are as follows:
Active HIGH discrete inputs: Input will go active with input voltages above 8.5V
Active LOW discrete inputs: Input will go active with input voltages below 5.0V
P691-61 Active HIGH discrete input.
P691-62 Active HIGH discrete input.
P691-63 Active HIGH discrete input.
P691-64 Active LOW discrete input.
P691-65 Active LOW discrete input.
P691-66 Active LOW discrete input.
3.2.5.4 Other Discrete Inputs (Not used)
The following discrete input pins are reserved for factory use.
P691-67 Discrete 2
P691-68 Discrete 1
P691-69 Test Enable
3.2.6 Remote Power ON/OFF Input
The unit will turn off if this input is pulled above 3 volts. The unit will turn ON if the input is left floating
or grounded. The input presents a load of greater than 100 kΩ.
P691-77 Data Link Remote power off.
3.2.7 Audio Out (GDL 69A Only)
The Audio Out provides stereo output for XM radio to be interconnected to an audio panel. The Audio
Out is affected by the volume controls, mute function, and suppression inputs. See Limitations Section
6.2 for requirements on use of suppression inputs.
P691-17 Audio Out Lo. This is the common ground for the audio output
P691-18 Audio Out Right. This is the right channel audio
P691-19 Audio Out Left. This is the left channel audio
GDL 69/69A Installation Manual
190-00355-02
System Interconnects
Page 3-5
Revision E