Have one 7200 and five 7100 nodes. All has been working. Customer is switching from cable ISP to fiber (new IP's). We moved the 7200 (call this A) first with not trouble. after switching the second unit ( B,first of the 7100's) A can intercom every site but B. B can intercom every site but A. Just last week we move the next 7100 (C). C could not intercom or be intercommed from any other site. We could ping the lan port C from site A. Any thoughts? Could we be missing something on the Samsung side. ty, Gary