well given the environment that the unit came from you should be able to figure out what range the ip falls in
ex: if the unit was on a network that had all the computers with a 10.0.0.xxx ip number, then the unit should have an ip in that range.
then you could do a ping of every ip on that subnet, " ping -b 10.0.0.255" or "ping -b 10.0.0"
this is all assuming the device responds to pings..
even if you do find an ip for the device, you will probably still need a user name and password.
Check with the manufactures website, to see if the have some diagnostic software to connect to the unit
Or how to reset it and start over.
I know that orinoco used to have software that would find the ip of heir AP's.
maybe other manufacturers have something similar...?