We are using a Triadis Floice system which can receive other Flarm traffic. Linked to a Garrecht TRX-1090 the traffic information gets mixed together with mode-S ADS-B extended squitter and can be displayed on any Garmin TIS compatible display with a RS232 interface.
Unfortunately the Garmin G500H in our helicopter is only accepting ARINC 429 and not RS232 as source for traffic information. We know that probably the following labels on the RS232 are used for the TIS.
Absolute Traffic:
$PGAV5,<age_of_position_data>,<hexaddress>,<lat>,< lon>,<gnssAlt>,<baroAlt>,<flightid>,<track>,<groun dspeed>,<verticalspeed>,<rssi>,<category>,<dataSou rce>,<rssiDistance>,<ageMDS>,<ageVelocity>,<agePos ition>,<squawk>*<nmeachecksum>
Relative Traffic:
$PFLAU,<RX>,<TX>,<GPS>,<Power>,<AlarmLevel>,<Relat iveBearing>,<AlarmType>,<RelativeVertical>,<Relati veDistance>,<ID>
The challenge is now to specify the exact ARINC labels (probably label 735) used by the Garmin G500H to display traffic. We have found a company that can program a converter to translate the data labels but we need to specify them first. Garmin is not willing to give us any information as the Flarm is not officially supported equipment. We could purchase a commercial TAS or TCAS but would still miss out on all the numerous gliders equipped with Flarm in the Swiss mountains.
Does anyone know the exact labels used by the Garmin G500H for traffic display? Thanks in advance.
You can easily answer this question by using an ARINC data logger on a TAS device. I guess larger avionics shops should have such a device.
What is the actual interface? Is it RS232 or ARINC429?
AFAIK, "ARINC" data is just textual (printable) data which can be viewed and captured with any dumb terminal with logging e.g. Terraterm.
There are also dumb ARINC429 to RS232 interface converters. I make interface converters for a living but have never done one of these, but I think the interface is close to RS422 (it's not tri-stateable so you have one transmitter driving a number of listen-only receivers, like RS422) so perhaps an RS422 to RS232 converter could be used to capture the data.
It would be nice if one could make a "data concentrator" box which would merge ARINC429 data from say a TAS605, and data from a FLARM receiver, and feed that out as ARINC429 into a suitable display product. Technically this should be easy (once the Avidyne TIS protocol is worked out) but I suspect there is a serious certification issue with it because the installation manual for it won't be permitted to show the connection to a non-certified FLARM box. However, there is, I believe, now, a certified FLARM box...
The concentration would need to be done intelligently because a given target is likely to be radiating both FLARM and Mode C 
Thank you both for the fast reply.
@achima: I am sure that this would work. But without a logger and a TCAS/TAS compatible with the G500H I was hoping someone would already have the information.
@Peter: My knowledge regarding specific details of the interfaces is limited to the information I could get from the manufacturer (in this case Garrecht). All I know is that the TRX-1090 can be configured to output traffic data (FLARM mixed with ADS-B) to GARMIN GPS series 39x, 49x, 69x and all devices with GARMIN TIS interface via RS232. The RS232 labels I mentioned above are from the data specifications published by Garrecht. All we know about the Garmin G500H is that it is capable of displaying traffic via ARINC429 from TCAS/TAS or ADS-B broadcast from a GTX-330 (which is not much good in Europe).
We are aware of the certification issues. Personally I think it just increases the general traffic awareness in our crowded Swiss airspace. As long as flight procedures are not changed and a good lookout is still maintained I can only see a gain in safety.
and all devices with GARMIN TIS interface via RS232
In that case it is coming out of an RS232 interface, which was to be expected because RS232 is cheap to implement - about €0.50.
To capture this data, you need any Windows laptop with Teraterm, and an RS232 port which can be a USB-232 converter.
I am fairly confident that I can find out how the data is sent out on the RS232 side. The big question is how the data needs to be structured on the ARINC429 for the G500H to show it on the MFD?
The big question is how the data needs to be structured on the ARINC429 for the G500H to show it on the MFD?
I tried to find out this information for some project a few years ago but found nothing.
It is either disclosed under an NDA only (to "approved" avionics developers), or everybody involved in making avionics which can display traffic data has reverse engineered it.
It would not be hard to reverse engineer it; you just need an ARINC 429 bus monitor (easy to make with an ARINC to RS232 converter, and a laptop with e.g. Teraterm) and an aircraft with a traffic system installed which you can hook it up into for an hour or so The Avidyne TAS products work fine on the ground so you would only need a bit of time in the plane, without flying.
You are right. Garmin certainly keeps the exact details very secret and those who managed to find out how it works rather keep it to themselves.
Although I am fairly good with computers I won’t be able to analyse the output of a TAS600 (or any other compatible equipment) as I don’t have one handy ?
A lot of pilots have the TAS60x systems installed. You need to speak nicely to one of these
Usually the "box" is installed in the back of the aircraft so getting to the right wire is not hard.
Hi. I’m looking for specyfication of Garmin TIS protocol or at least maybe dump of tis sentences.
I would like to built experimental project on arduino able to display traffic points on 695.
Maybe someone have any materials about it?
