Yeah, that manual is not very helpful as it does not have any of the programming codes. I didn't exactly get the answer I was looking for, but I was able to turn the ringers back on the other phones by copying a ringing phone's configuration to the other non-ringing phone.
I found the programming codes here:
http://www.alphatelecom.ca/norstar_feature_codes.htm
I couldn't find the answer, so I had to find a work around.