How to find IP device static IP address if unknown

Download wireshark, and start monitor the IP traffic and turn off/on IP device,  then it will start broadcast  and you can see the IP address

http://www.wireshark.org/

below is a ARP, 10.199.91.103 is the IP address

89 108.722425000 DelphiDi_02:cb Broadcast ARP 60 Gratuitous ARP for 10.199.91.103 (Request)