What is the possibility of these news jets are just here for trails at the moment. Yeah trails can happen in China as well but we want to test them in our semi Western environment. J15s as claimed is purely Chinese built and integrated with Chinese eco system where as our systems are mostly western. We may like to test their interoperability and compatibility with our data link 16, Saab Awacs, western ground based radars etc etc before saying yes to them. That's is why so much secrecy is being maintained.
I think it was probably on Quwa that I read...or maybe some other news source which said that some sort of a bridging solution is in place...
...PAF has net centricity...all the data communicated via Link 16 and Link 17(plus whatever other datalinks that may be in use) all gets combined to make one comprehensive picture.
While I don't know the exact details but I think it works like this...
An F16 on patrol picks up a target on its radar(let's say an IAF Su30 flying across the border)...it relays that info over to the Erieye(which has Link 16 and the customer can also use their own TDL as per SAAB...so presumably it also has Link 17) flying nearby. Somewhere else a little further out a JF17 picks up another target...it also relays to the Erieye...
...the Erieye is receiving all the info from two separate western and Chinese platforms...while also sending out the info to these assets(JF17 can now receive data regarding the Su30 MKI that the F16 had detected). Essentially the Erieye is working as the go between for the two jets of different origins. The same go between type of thing can be done using a ground station...where the data is received from multiple different sensors of different origins.
So if such a thing is already in place with previous jets of Chinese origin(JF17, ZDK, F7?)...no point in testing it over and over again with J10 and J15.