User Guide

12
Suitability for use
The AV Unit is suitable for household, office and similar indoor use when connected to
direct exchange lines using Loop-disconnect or Multi-frequency dialling.
It is not suitable : (i) as an extension to a payphone (ii) for use on shared services or a
leased line system.
Note : Apparatus is treated as connected directly to the PSTN line if it is connected to
the PSTN via a Relevant Branch System (RBS). For definition of an RBS refer to
BS6789 Section 6.1, Clause 2.4
Note : The AV Unit is not intended to be used to answer naive callers.
A naive caller is a caller with no special knowledge of the characteristics of the auto-
answering system who would not have reason to expect an answer to be unusually
delayed or who would be uncertain how to act without guidance from the answering
system. (Refer to BS6789 Section 3.2, Clause 2.6)
CONNECTION REQUIREMENTS
Safety
All terminal connections are SELV (Safety extra-low votage) type circuits and only SELV
type circuits must be connected to these ports (for definition refer to EN60950 : 1992
clause 2.3)
Supply
The AV Unit requires a Fused (1A) nominal 12V d.c. supply to terminals marked
SUPPLY observing polarity. (see Statutory Requirements on page 7 for further details of
power supply conditions)