hello guys , i have a quick question, when our a/c and other a/c both have tcas 2 and mode c( in 1 a/c) and mode s( in another a/c), it gives TA+RA, now when both the a/c have tcas2 and mode s, it gives complementary RA using the datalink system ..what does this mean? how does this differs from the 1st case, besides tht it inform the ground controller automatically. thanks in advance...