Hello everyone. I've asked many questions for my project of C-bus,and all those has been hurdled with the help of my friends in this forum. But a new problem was found. >_<||| I have a light project which controlled by C-bus.My system have four networks and collected by four bridges(5500NB),I named them "network 1"to"network 4". My project has been finished,and the system were running stable in passed January.Five days ago,I updated my software Toolkit(1.1 to 1.6),two days passed,when I was checking my system,I found network 3 in my project was break off suddenly. As everybody knows,sometime the network may break by some little problems,so I tried to re-scan my networks,but I failed.I checked my units and setting,no problems. My syetem's condition: 1,unit numbers in trouble network: 93,not contain 5500PS 2,length of trouble network: about 600m 3,a sketch map: there's 30 floors in my building. 5500PC------5500NB---PACA---network1-----1-10F ````````````` | ````````````` | ````````````` | ````````````` | ```````````5500NB---PACA---network2-----11-20F ````````````` | ````````````` | ````````````` | ````````````` | ```````````5500NB---PACA---network3-----*|-----21F (21units) ````````````` |`````````````````````````|-----22F (23units) ````````````` | ````````````````````````|-----23F (27units) ````````````` |`````````````````````````|-----24F (22units) ````````````` | ```````````5500NB---PACA---network4-----25-30F The phenomena of the problem: 1, only network3 has the trouble. 2, In Toolkit,when I click the button "Scan network",sometimes the software told me:"could not scan network,please check your connection".But sometime I could get only one unit,the 5500PC,or sometimes I get two units,the 5500PC and a c-touch in 24F. 3, If I click "Scan new units" button,sometimes it told me connection error,sometimes I could get about 60 units in the network! 4, I uesd the multimeter tested my cable from PACA to network3,and the cable was well. 5, If I take out one floor,for example 21f,I could get units in other 3 floors,but the speed of scanning was very slowly,and when scanning finished,I double click the unit in dexter list,Toolkit could not load the units state from my physical network,but ask me:"is the unit on your network?" 6, IF I scan my units in the '*' point(look my sketch map),I could get all my units,it looks like there's an error in the cable which from PACA to net3,but,the cable was well! Please help me,thank you.