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Connecting EFIS audio to intercom

Marty G

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I am trying to connect my GRT Horizon 10.1 EFIS 'Audio Out' and I'm not exactly sure the best way to get the audio through my intercom.

I have a PS Engineering PM2000 intercom, but the wiring diagram doesn't have a clearly defined place for this type of input.

Am I missing an easy solution? Do I just tap it into a mic wire somewhere and that's it??

Any help is appreciated.

Marty
 
that intercom should have both a switched (likely just labelled as audio) and un-switched audio input pins. Ground goes on the common. Assuming the EFIS is giving alerts, be sure to use the unswitched audio, otherwise the radio voice will mute the alerts.
 
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Diagram

Here's a wiring diagram of my intercom. Any chance you could look at it and help me figure out which would be my unswitched audio?

The only thing I see that seems possible is the "A/C Mic Audio Lo" and the same but "Hi". This seems to be for rigging an old handheld auxillary microphone if I'm interpreting it right.
 

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I do not think the PS2000 has more that one audio input (except for the AUX/Music input that is muted with any intercom transmissions), but I could be wrong.

What I'm doing is address this issue on my Flightcom 403 is adding the Gretz Audio Mixer from Aircraft Spruce into the system. This mixer allows up to 9 audio sources to be mixed and fed to the intercom. Each source can be individually adjusted so you have a consistent level of volume across the sources. Currently my 430W has the COM and NAV audio tied together, which works, but I get some bleed over from the NAV morse code identifier into the COM even with the volume on the NAV is all the way down and not selected on the 430 to identify. The point of my adding the mixer is to get all the aural warnings from the autopilot, EFIS as well as my handheld GPS.
 
Maybe I am barking up the wrong tree with the intercom. I also have a KMA 20TSO audio panel. Should I be trying to route it in there somewhere rather than the PS Intercom?
 
Maybe I am barking up the wrong tree with the intercom. I also have a KMA 20TSO audio panel. Should I be trying to route it in there somewhere rather than the PS Intercom?

Yes audio panel is where you should be sending the audio, it for sure has an unstitched pin for alerts.

Good luck!
 
I ran the audio output from the GRT Horizon to Pin #5 on the KMA20 and I'm not hearing any audio alerts. Is there anything I need to do on the audio panel to activate them? There doesn't seem to be any switches on the face that would suggest so.
 
A simple solution for most EFIS systems is a resistive summer (Note: I haven’t done this with GRT).

Each of the red splodges is a 150 ohm resistor. Connect a stereo efis to the L&R points. For mono EFIS, connect L&R together.

Replicate for the copilot headset.

The advantage of this no externally powered device is required.

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Did you set up the alarms in your efis? IIRC (I may not) you go to the General set up page, scroll down near the end. There are lots of alarms to turn on or off. I think maybe you can set volumes there too. If you have adsb-in definitely turn on the traffic alarm.
Side note: when setting up the alarms, I brought the 3 audio wires (left, right, ground) out of the efis, and terminated them in a 1/8” (I think) audio plug. I plugged it into the music jack located on the battery pack of my Lightspeed headphones, for testing. It worked fine, and I decided to leave it that way, so passengers don’t hear the alarms, just left front seat. Going thru the unswitched input on your audio panel should work okay, too, but everyone will hear all of the alarms, I think. Some passengers want to hear them (especially ‘traffic’) but some may not want to hear them.
 
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