If anything is wired to the orange/white pair, it is likely that the station jack has been modified to allow this pair to work with a phone or analog port. For example, if a splitter is plugged into a jack, then the blue/white pair (the center pins of the jack) are split to the first port (typically the left side) of the splitter. The orange/white pair of the jack are then "remapped" to the sencond port (typically the right side) of the splitter. Such splitting can also been accomplished behind the faceplate of the jack and then the outlet has two jacks (or more) wired on the same cable run.
The Nortel digital phones only use the white/blue pair of a standard jack. Same for analog. IP phones are different, since they wire to an Ethernet jack, but then the connection to the Nortel BCM is via a network link, not the 25-pair amphenol connector.
