Yes, you would access the pbx in pdt mode.
Then you would access the correct line of code using the switch release as your primer.
Then you take this hex number and print out all the lines of code that decipher them with the secret nortel decoder ring. <-- You think i'm being tacky here, but there is a decoding table
Then you get out of the pdt mode and log into the switch.
Sounds easy enough, but you need the pdt password, which you won't pull out of anyone that knows it. Then you need to know which lines of code to go to, and then you need to know how to decipher those lines of code. I say they are in Hex format, but actually I think it's NortelHex.
Sometimes I read posts that sound cold when referring to the pdt passwords, but it's for safety. So please don't think i'm being cold when I say, call your provider. Nortel does charge for the password crack, but more importantly your provider should be able to do this.
Approx cost is $300 - $1500 depending on the mood of the tech doing the password crack.
John