I have two tables.
First LOCATION with fields:
-CU serial number
- communication unit:device type
Second COMMUNICATION UNIT with fields
-manufacturer (ABB, SIEMENS,.........)
-serial number (123, 432,.........)
-device type (modem, router, converter)
Relationship between CU serial number and serial number . When type serial number in CU serial number everything is fine. But now i have more than 1 communication device per address. For example two routers or 2 routers and 1 converter. I can not handle that.