BT have checked everything as have sky and everything is working. B&O have checked by BEOCOM6000 (MKII) and caller ID works in their shop. So everything works! Except it doesn't in the house. A normal phone plugged into the socket has caller id but not the BEOCOM600. If they are both plugge in together, neither phone has caller ID. I am a customer of Sky and have their Sky talk package including caller ID. No-one can figure out why my caller ID won't work. Any help out there?

Maybe your REN?

"Effects of overload. If the total allowable REN load is exceeded, the phone circuit may fail to ring (or otherwise malfunction. See call waiting and caller ID). In extreme cases, the telephone service provider may temporarily disconnect an overloaded line to reduce load. Call waiting and caller ID are often affected by high REN. Older (pre 2000) equipment contributes larger REN than new equipment."