I have a customer that purchased a used IPO 403 off the internet. I know, bad idea, but none the less, they did it as a backup to their existing 406. Problem is, I can't access it to program it. There is an IP address posted on the front of the control unit, but that did not work.
I also tried the default IP address according to the documentation I have (192.168.42.1) and that didn't work either. Any ideas on how to "hack" into the machine to program it, or how to factory reset it?
Thanks.

System documentation provides specific instructions on DTE reset. Be sure to follow docs to the letter.
Mike