Air Avionics have provided a document covering the connection of uncertified GPS devices to their VT-01, VT-02 and VT-2000 transponders to enable ADS-B Out, which can be accessed here:
FASVIG is highly supportive of initiatives to increase the voluntary adoption of ADS-B in General Aviation and is working to help make the implementation of ADS-B Out as quick, simple and cost effective for users as possible.
One of the challenges for GA pilots is understanding which transponder makes and models and even which specific firmware levels support the ADS-B technical requirements for use with an uncertified GPS. Transponder manufacturer support for this is patchy to say the least and authoritative information has been lacking.
FASVIG is keen to encourage transponder manufacturers to support ADS-B configurations that incorporate an uncertified GPS position source and to make supporting information readily available.
Transponder manufacturers are invited to provide details to FASVIG of their product support for ADS-B Out with uncertified GPS position source and in return FASVIG will publish the information here on our website. This will greatly simplify the task for pilots wishing to select products at the purchasing stage and then to make use of ADS-B technology to enhance the safety of themselves and those sharing airspace with them.