If no DHCP is in use the only methods for configuration of an IP v4 address that I am aware of are APIPA (Automatic IP Addressing), which assigns an address in the 169.254.x.y/16 range, or static address assignment, which will set the IP address either to a pre-configured setting for that particular device or to some address that you manually configure.
If the device is configured to use a particular static address it should be listed in the documentation for that device. If you set the address yourself, then obviously you will already know it. And if the address is set by APIPA it will be in the aforementioned range of 169.254.x.y/16 (the /16 refers to a subnet mask of 255.255.0.0 in case you are not familiar with CIDR notation).
To find the exact address you would need to scan the known address range to find the particular assigned address. You could use nmap, unicornscan, etc...


