A method and apparatus for converting an iron-bearing residue generated in a hydrometallurgical process that contains small amounts of soluble heavy metals into a stable form by means of a neutralising agent. The system further includes a second database storing information for the plurality of building automation subsystems. The first and second pairs of contacts may be disposed along the pair of opposing sidewalls, projecting at least partially into the socket configured to contact and exert substantially the same normal force on a male terminal that is inserted into the socket. One of the projection and the recess are offset relative to the other of the projection and the recess to accommodate the spondylosed relationship between the first and second vertebrae.