APPENDIX A A - 9
Using extension telephones (For U.K. only)It may be that your premises ar e already wired with par allel extension
telephones, or you intend to add extension telephones to your line,
in addition to your machin e. While the simplest arrangeme nt is
straightforward paralle l connection, there are some reas ons as to
why this arrangement will cause unsatisfactory service, the most
obvious of which is inadve rtent interruption of a facsimil e
transmission by someone p icking up an extensi on telephone in or der
to make an outgoing call. Ad ditionally, Fax receive code m ay not
operate reliably in such a si mple configuration.
This machine may also be set to make a dela yed transmission (i. e. a
transmission at a pre-set time). This pre-set job may coincide with
someone picking up an extensio n handset.
Such problems can easily be el iminated however, if you arrange
modification of your extension wiring circuit, such that extension
devices are connected “downs tream” of your machine, in a
master/slave configurat ion (see fig. 2 on next page). In suc h a
configuration, this 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-ho ok detection.”
The inadvisable configur ation is shown in figure 1 on the next page,
and the recommended maste r/slave configuration i s shown in figure
2.
This new connection configuration can be arranged by contacting
BT, Kingston upon Hull Telecommunications, your PABX maintainer
or a qualified telephon e installation company as appropriate. Simply
explained, the extensi on telephone circuit sh ould be terminated o n a
normal modular plug (BT 431A style), which in turn should be
inserted into the modular socket of the white “T”-shaped conne ctor
provided as part of the line cor d assembly.