Operation Manual

Chapter 6
34
Using extension telephones
(U.K. only) 6
Your premises may already be wired with
parallel extension telephones, or you may
plan to add extension telephones to your line,
as well as your machine. While the simplest
arrangement is a straightforward parallel
connection, there are some problems with
this arrangement, the most obvious of which
is inadvertent interruption of a facsimile
transmission caused by someone picking up
an extension telephone to make an outgoing
call. Also, remote activation code may not
operate reliably in such a simple
configuration.
This machine may also be set to make a
delayed transmission (i.e. a transmission at a
pre-set time). This pre-set job may coincide
with someone picking up an extension
handset.
These problems can easily be eliminated, if
you arrange modification of your extension
wiring circuit, such that extension devices are
connected “downstream” of your machine in
a master/slave configuration (see fig. 2). In
this configuration the machine can always
detect whether a telephone is in use. Thus it
will not attempt to seize the line during that
time. This is known as “telephone off-hook
detection.”
The inadvisable configuration is shown in
figure 1, and the recommended master/slave
configuration is shown in figure 2.
This new connection configuration can be
arranged by contacting BT, Kingston upon
Hull Telecommunications, your PBX
maintainer or a qualified telephone
installation company as appropriate. Simply
explained, the extension telephone circuit
should be terminated on a normal modular
plug (BT 431A style), which in turn should be
put into the modular socket of the white “T”-
shaped connector provided as part of the line
cord assembly.
Inadvisable connection of extension
sockets (Fig. 1.)
6
1 Extension socket
2 Master socket
3 Incoming line
Recommended connection of extension
sockets (Fig. 2.)
6
1 Extension socket
2 Master socket
3 Incoming line
The fax machine must be plugged into the
master socket.
Note
These telephones are now connected as
external devices (see Connecting an
external or extension telephone
on page 33), because they are connected
to the fax machine via the T-connector.
FAX
11
2
3
FAX
11
2
3