Hi Peter,
I have had the following back from our Director of Surveillance.
• Will TAS-A with ADS-B show ADS-B targets on my display?
o The TAS-A continues to support all of the display interfaces that it did previously, and all of the detected targets (even those that are ADS-B only) will be displayed on all interfaces.
o We did not make any changes to the existing interfaces to avoid breaking any installations.
o Since the currently supported interfaces were designed for TAS/TCAS displays the ADS-B targets will not look any different from the TAS targets.
o The best source of data is selected for each target based upon all of the sources available for that target (TAS / ADS-B / TIS-B / ADS-R in the US).
o We plan to add support for additional interfaces that will support the additional ADS-B data, but we plan to support all traffic sources over the existing interfaces indefinitely.
• What are the GPS requirements for TAS-A with ADS-B functionality?
o An ADS-B compliant WAAS GPS source is required in order to show any ADS-B traffic (hybrid or ADS-B only); however, TAS traffic is tracked whether GPS is available or not.
o The TAS-A will declare a caution condition if a GPS source is not available, or if the GPS accuracy/quality does not comply with ADS-B requirements.
o The ADS-B functions can be disabled so that the equipment continues to function as a TAS unit without ADS-B functionality. A GPS input is not required when ADS-B functions are disabled.
o The TAS-A will continue to track and alert on TAS traffic even if ADS-B functions are enabled and the GPS source is not present or is inadequate; however, some display interfaces do not differentiate between caution and failure conditions and will not display traffic while the GPS caution condition is present unless the ADS-B functions have been disabled. Audible alerting for the TAS traffic will still be active in this situation.
This sounds excellent, Steve.
What “W” GPS sources have been tested with the new TAS605? My preference would probably be a GTX345, in the short term until I get a new centre stack.
if the GTX345 is outputting a WAAS signal then you can use that no problem, the TAS A when ADS-B in is enabled is just requiring the WAAS GPS position.
The GTX345 has a WAAS GPS option inside. My Q is more whether anybody has used it for feeding the TAS605-A.
There is some history to this multi-vendor compatibility aspect e.g. the GTX330’s ARINC429 pressure altitude data was not compatible with the TAS605 (non A). There is a post here somewhere, by what looked like an avionics installer in the US, that firmware version X fixed that but I can’t find it.
Someone asked me today why, if installing a GTX345, why not use the GTX345’s traffic data merging capability to merge the data from my existing and non ads-b in upgraded TAS605, with ADS-B IN data from the GTX345, and display the merged data. That would save me the TAS605 upgrade cost.
I scratched my head at this… and then remember that, probably, the reason for not going that route was the complete impossibility of establishing whether the ex-GTX345 merged traffic data will display on the KMD550 and the two SN3500s! In fact a guy at Sandel told me the SN3500 cannot display any ADS-B targets! That is obviously not universally true (in the light of Steve’s post above) but it could be right for the SN3500 receiving the GTX345 data, and if that happened, both parties would wash their hands of it – Garmin because they are a big company, and Sandel because they already told me it won’t work 
And the KMD550’s ability to display GTX345 data is even more completely unverifiable… All this was posted here before and nobody knew the answers. The stuff is just a bit too obscure.
If I upgrade the TAS605 to ADS-B IN, I ought to find the simplest/cheapest WAAS GPS source for it. There is the Trig TN72 but who can say if it will work?
I’m curious as to how the Sandel unit would know a target is ADSB, coming from the GTX345. Sounds odd.
Different symbols are used on the display, apparently. But the Sandel guy told me the protocol is different, which didn’t make sense to me (he is not one of the developers, and I could not get anything from anyone “deeper”). The world is full of people guessing
Obviously using different symbols is optional and Avidyne didn’t do that which is a lot more compatible.
GTX335
With reference to my post above, could a GTX335 (not 345) with the WAAS GPS option be used as the WAAS GPS source for the ADS-B IN upgraded TAS605?
It could then provide ADS-B OUT also.
The ADS-B IN functionality (and target merging) of the 345 would not be needed in this case.
Would anyone guarantee compatibility between the 335 and the TAS605 (ADS-B IN upgraded)?
Is there any other transponder out there which would do a similar job?
Perhaps @steveavidyne might be aware of any installations?
Peter,
I see the GTX 3X5 units have support for ADS-B Out+ protocol from a serial port. There are two possible baud rates supported. The ADS-B Out+ protocol is Garmin proprietary but some competitors have reverse engineered it and others have licence agreements with Garmin. If Avidyne supports the protocol, it should work as a position source. In the case of ADS-B Out systems, the position source and ADS-B Out system must have an STC for the pairing, but I don’t think this would apply to ADS-B In, which is your usage. The GTX 3X5 already support ADS-B Out with the built in position source option. Avidyne would have to claim they support the Garmin position source protocol via a serial port using ADS-B Out +.
I am happy to install the TAS605 “A” upgrade and replace the GTX330 with a GTX335.
ADS-B IN via the TAS605A, and ADS-B OUT via the GTX335. And no need to do any data merging which would require the GTX345 and introduce a raft of compatibility issues.
I have a location available in the composite roof for one GPS antenna, which the GTX335 would need.
The Big Q is whether any installer is willing to talk to Avidyne to get a loan TAS605A box, put it next to my old one, plug it in, and with a suitable tester which simulates targets in both C/S and ADS-B OUT categories, make sure it still works with my three display devices (2 x SN3500, KMD550).
