Sharp UX-470 - Manual (Page 20)

Other devices
If desired, you can connect an extension telephone to the same line as
your fax. This can be used to make and receive calls as normal. For
details on initiating the receipt of faxes from an extension phone, see
"Receiving Dcouments" in Chapter 4.
Comments:
••
More than one extension telephone may be connected to the same line as the
fax, provided the total REN value does not exceed 4.
••
The TEL.SET socket (sealed with a protective cover) has been provided on
the back of the unit. The safety status of this socket is TNV, and is provided
for the connection of approved telephone equipment only where appropriate.
To ensure continued safety compliance, do not connect any other equipment
to this socket.
Connections
18