This is used by PXM to determine if this end point is master or slave, a new type unknown is added to identify the SM in MGX8220 shelf and the SM in MGX shelf. In AXIS shelf, user can still use addchan to add a channel without specifying X/Y/P parameters. But in MGX shelf, if the user uses addchan without X/Y/P set (based on this object being set to type 3 unknown), SPM on PXM will reject the request. It must be supplied in connection setup request. In the feeder mode, this is always set to master.