I have a customer who has a CS1000e 5.5 with all the latest updates and firmware. When the HMS400 is connected to any cabinet on the system it causes the MGC to reboot at random times. No error codes come up at all. Nortel was no help on this issue but they did go through the switch with a fine tooth comb and found no issues that would cause this. Nortel suggested the PMS link be moved from the main cabinet to one of the others which has been done but has not solved the issue.... Any ideas would be helpful!