BT Business Total Broadband Quick Reference Manual page 13

Landline cable (optional)
With the landline cable fitted:
you can make calls using your business telephone number from the phone that's plugged
•
into your BT Business Hub by dialling '5' before the number you wish to call. If you don't dial
'5', you'll make the call using BT Business Broadband Voice
the phone plugged into your Hub will automatically use your main telephone line to make
•
outgoing calls if there's a power cut or broadband service failure
Plug the purple connector into the purple DSL socket on the back of your Hub and plug
the other end of the cable into the telephone socket on your master socket or a telephone
extension socket.
Quick reference guide
13