APPENDIX A A - 8
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 MFC. Whil e the simplest arrangement 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 MFC 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 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 “d ownstream” of your MFC, in a master/slave
configuration (see fig. 2 on next page). In such a configuration, this
MFC 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 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.