I have just installed a new 5504GI (it has been connected between two existing units, and they are both ok, so no cabling problems). I have not yet connected the external 24v supply (it should arrive tomorrow) but don't think that should affect programming the unit? I set the unit up in the database first, then connected it up. I then successfully used Toolkit to change the unit address from 255 to 250 which matches what I put in the DB. If I try to save the DB programming to the unit, the progress bar doesn't move from 0% and then I get a 45027 "Unit transfer failed" error. If I try to open the unit from the Network, the progress bar gets to 1% and then I get a 20044 "The unit you selected failed to load". I have C-Gate running remotely and all I am getting in the log is "INFO | jvm 1 | 2006/03/16 18:17:08 | 20060316-181708 751 //jubilee - Tag information changed at tag address: //jubilee/!7aed1ec0-9695-1028-836b-98426950828d oldtag: Sensor Interface newtag: Sensor Interface". Thoughts welcome. Thanks. Nick