best AT command to detect network

what is the best AT command to detect that a device has joined a network. I see the ATJN command but that’s not available on my devices. I only have two devices on the network. I am using the 802.15.4 xbee S1.

802.15.4 does not require Joining or what is referred to as Association for communications to occur. In this case the best option is to issue a Node Discovery or simply add that function into your application code with some sort of broadcast transmission with an ACK.