@prashanth I have seen that TTN uses SF9 @ 869.525 MHz for the RX2 response. There is a rational that a gateways can send with higher power at that frequency, and therefore cover the same distance, while having shorter transmission times. That works, if the node has been connected with OTAA. In that case the RX2 parameters are sent to the node. I was a little bit surprised when I stumbled over that.