BT PaperJet 40 - Manual (Page 9)

…To separate sockets
You can also connect other devices to the same line even if they are
in different rooms, but you will not be able to use certain functions,
for example, being able to transfer a call from your BT PaperJet 40
to a telephone.
Getting started 9
BT PaperJet 40 UG – Issue 2 – Edition 2 – 18.03.04 – 6026
Connecting to a switchboard?
To set up switchboard/PBX connection, see
page 50.